40 Gallon Tank 40 Gallon Long Reef

I am new to saltwater but have kept multiple freshwater tanks. Recently a friend gave me a 40 gallon long tank. I have looked into saltwater and wanted to have a simple care reef tank. Does all of this look good?
-Equipment-
Aqueon Pro 200 Watt
Marineland C-220 Caniuster Filter
Innotive Marine Skimmate Protein Skimmer
Refractometer
Digital Thermometer
Fluorescent Hood that came with tank(Uses Coral life T12)
-Fish-
2 Clownfish(A. ocellaris)
1 Azure Damsel(C. hemicyanea)
1 Yellow Clown Goby(G. okinawae)
1 Orange Spotted Goby(A. guttata)
-Inverts-
1 RandallI Shrimp(A. randalli)
5 Bumble Bee Snails
4 Nerite Snails
1-2 Feather Dusters
-Corals-
1 Toadstool Mushroom Coral
1-2 Blue Cespitularia
1 Finger Coral

Anything I should get rid of or add? I plan on having 10-20 lbs of Live Rock and 20 lbs of Dead/Dry Rock. I will use 40 lbs of Caribsea Pink FijI Live sand. Thanks in advance!

 

If your planning to keep the tank in the long run and progress trough the reefing hobby you will want to get rid of the canister filter.just do your research and have patience .You will enjoy the salty side of the hobby

 

Welcome to the salty side!

Definitely nix the canister filter. Everything else seems okay though... I don't see a powerhead on your list so I'd look into those. Flow is very important in reef tanks! If you're looking to expand into more demanding coral, you'll also want to think about upgrading your lights, which can be a pretty penny but worth the expense in my opinion.

As for stocking, I'd say to watch for aggression between the clowfish and damsel..and you need a crab!

 

Agreed. Ditch the Canister filter and go with a Fluval 70 or 110 HOB. Canister filters are the most labor intensive and problematic means of filtration with saltwater tanks, they are very prone to trapping the nasties and becoming nitrate factories. Powerhead or Powerheads (since it is a longer tank) would be recommend. Hydor Koralia 3rd gens in the 1350 gph or higher range would be good.

 

Ok, ditch the canister and get a powerhead. I read somewhere though that the mushrooms don't like a lot of flow?

Welcome to the salty side!

Definitely nix the canister filter. Everything else seems okay though... I don't see a powerhead on your list so I'd look into those. Flow is very important in reef tanks! If you're looking to expand into more demanding coral, you'll also want to think about upgrading your lights, which can be a pretty penny but worth the expense in my opinion.

As for stocking, I'd say to watch for aggression between the clowfish and damsel..and you need a crab!

What type of crab would be best? Will iI not attack the 2 Gobies and Pistol Shrimp.

 

The smallest hermits (ie reds and blues) would probably be best. The larger crabs are cool looking but are more likely to be a nuisance to your life in your tank. As for attacking the Goby or Pistol Shrimp? I wish any crab good luck with that one. Keep in mind the Pistol Shrimp has it's name for a reason and the Pistol and the Goby have a Symbiotic Relationship. I know my Diamond Watchman Goby would actually pick up hermit crabs in it's mouth that tried to go into it's den and forcefully spit them out. It would do it hard enough that they would tumble and the crab's shell would hit the glass. Freaked me out for a bit hearing the repeated popping/tapping sound against the glass until I figured out what was going on.

 

Ok, the Goby and Shrimp are safe, but while reading about the red Tip Dwarf Hermit and the Electric Blue Hermit several sources said they might attack the snails for their shells? If I give them enough will they be fine or should I do snails or crabs.

 

Ok, the Goby and Shrimp are safe, but while reading about the red Tip Dwarf Hermit and the Electric Blue Hermit several sources said they might attack the snails for their shells? If I give them enough will they be fine or should I do snails or crabs.

If you add extra shells it will cut down on the likelihood that they will kill snails for their shells, but honestly you will have to be prepared to sacrifice a few snails every now and then. To me though it's a small expense, particularly for a reasonable sized tank like a 40 gallon. The problem is that crabs and snails do overlap on some basic algae eating functions but from there they differ quite a bit. Crabs also eat detritus (fish poop) and excess food bits around the tank, snails on the other hand are almost exclusive algae eaters (although a fighting conch snail has a more varied diet like a crab). If you plan on having a sandbed, I would get 1-2 conch snails as they will do a great job of cleaning your sandbed without creating a sandstorm. I have 5 of them in my 90 gallon and they do an amazing job. They are super hardy and know how to outwit any pesky hermits that might bother them (I have seen it in action in my own tank). You will want some other kind of snails for keeping your glass clean though.

 

I plan on having Nerites and Bumble Bee so that should be fine for the glass. I thought the Gobies sifted through the sand for part of their diet?

Is there any other fish I could get that occupies the mid-bottom of the tank? I like eels but the dwarfs are $400 and the other ones get too large. Are there any species of Blenny(Bicolor or Tailspot) or Dartfish(Firefish or Scissortail) I could keep? Also what is the best order to add the fish and inverts to the tank, I was planning on-
Month 1-2: Cycle, Set Up Tank
Month 3-4: Add Corals(Coral every week or two)
Month 5: Add Snails, Feather Dusters, and Crabs
Month 6: Add Gobies and Shrimp
Month 7: Add Clownfish and Damsel

 

Is there any other fish I could get that occupies the mid-bottom of the tank? I like eels but the dwarfs are $400 and the other ones get too large. Are there any species of Blenny(Bicolor or Tailspot) or Dartfish(Firefish or Scissortail) I could keep? Also what is the best order to add the fish and inverts to the tank, I was planning on-
Month 1-2: Cycle, Set Up Tank
Month 3-4: Add Corals(Coral every week or two)
Month 5: Add Snails, Feather Dusters, and Crabs
Month 6: Add Gobies and Shrimp
Month 7: Add Clownfish and Damsel

I’m still shaky with some saltwater stocking advice but I have a tailspot and I love him! He’s active and full of personality and will help consume some algae as well.

If it were me, I’d add fish first, starting from least aggressive and working your way up to most aggressive and QTing all new additions to save yourself future headaches if possible. Once you feel good about keeping livestock, then introduce your corals. That was my process, but I feel like this question has more than one right answer so I’ll just leave you my opinion here. I was pretty nervous taking the plunge into sw which is why I chose to first focus on keeping a fish alive and healthy and worry about keeping corals later, since I thought I might want to devote extra attention to learning about and keeping them; after all, I’ve kept fish before, but never coral!

 

The Corals and Gobies are going to be my main part so I wanted to see if I could actually keep coral or if I would have to restart on the stocking. Is there any other corals that I could add possibly?

 

I plan on having Nerites and Bumble Bee so that should be fine for the glass. I thought the Gobies sifted through the sand for part of their diet?

Certain Gobies will sift sand to an extent but only a handful will really do the job well enough (ie Diamond Watchman, Gold Head Sleeper Goby, Court Jester Goby) and of the two you are getting, only the orange spotted goby will sift any sand and I am not sure how good of a job it will do. Are you sure they are Nerite or are they Nassarius snails? I would personally skip the Damselfish. They can be jerks to their tank mates and make it harder to add new additions in the future. Definitely add the clownfish last as they can be ultra territorial once established. As for the Dartfish (ie Purple Firefish and Scissortail) they are pretty and interesting fish, but they also tend to be very timid and are among the most easily bullied fish in the hobby. I can tell you after having both a Purple Firefish and a Scissortail, I will never own another dartfish again. They spent more than half the time in hiding (basically only coming out to feed) and were the number one target for any fish that was even remotely assertive (My snowflake clown picked on my scissortail to no end). They are also nearly impossible to catch or trap, so they effectively become nothing more than an unwanted source of nitrates. I prefer visible fish. If you are looking for a smaller fish that will be more active and visible, I would strongly suggest looking into either a pink streaked or flasher wrasse. Wrasses are THE MOST underrated fish in the hobby and they will give you far more personality, color and activity rather than a dartfish that hides the moment it gets scared of it's own shadow. You just need to be sure you have a good fitting lid on your tank (which you will need regardless as Gobies are prone to jumping as well and ALL FISH will jump at some point). Here are some Wrasse options for you:






Don't be put off by the 55 gallon minimum listed for the Flasher Wrasse as they will do fine in a tank that is 48 inches long. They are super active guys though.

If you don't mind risking the occasional snail and crab, (it should leave the snapping shrimp alone) a Red Lined Wrasse could also work:

 

I thought of Wrasses but they can be aggressive to corals and inverts I read. The snails are going to be Nerites. I like the Azure and I have looked into them, from what I read they are the most peaceful Damsel and will not start fights but will not be bullied. Also for the equipment I changed some things and added others,
I will get a RO System
The Filter will be a Fluval 70
The Skimmer will now be a Aquatic Life instead of Innotive
I will get a Hydor Koralia Evolution 750-850
Should I change anything or is it all fine?

Certain Gobies will sift sand to an extent but only a handful will really do the job well enough (ie Diamond Watchman, Gold Head Sleeper Goby, Court Jester Goby) and of the two you are getting, only the orange spotted goby will sift any sand and I am not sure how good of a job it will do. Are you sure they are Nerite or are they Nassarius snails? I would personally skip the Damselfish. They can be jerks to their tank mates and make it harder to add new additions in the future. Definitely add the clownfish last as they can be ultra territorial once established. As for the Dartfish (ie Purple Firefish and Scissortail) they are pretty and interesting fish, but they also tend to be very timid and are among the most easily bullied fish in the hobby. I can tell you after having both a Purple Firefish and a Scissortail, I will never own another dartfish again. They spent more than half the time in hiding (basically only coming out to feed) and were the number one target for any fish that was even remotely assertive (My snowflake clown picked on my scissortail to no end). They are also nearly impossible to catch or trap, so they effectively become nothing more than an unwanted source of nitrates. I prefer visible fish. If you are looking for a smaller fish that will be more active and visible, I would strongly suggest looking into either a pink streaked or flasher wrasse. Wrasses are THE MOST underrated fish in the hobby and they will give you far more personality, color and activity rather than a dartfish that hides the moment it gets scared of it's own shadow. You just need to be sure you have a good fitting lid on your tank (which you will need regardless as Gobies are prone to jumping as well and ALL FISH will jump at some point). Here are some Wrasse options for you:

Don't be put off by the 55 gallon minimum listed for the Flasher Wrasse as they will do fine in a tank that is 48 inches long. They are super active guys though.

If you don't mind risking the occasional snail and crab, (it should leave the snapping shrimp alone) a Red Lined Wrasse could also work:

It says on your link that the wrasses might eat feather dusters and snails. I like the Mckoskers Wrasse.

Forgot to ask, would a Candy Cane Coral be okay, I have read mixed reviews on their care and compatibility.

Would this stock work? Tank is 48"x12"x16"
Fish-
2 Ocellaris Clownfish or 2 (A. polymnus) Saddleback Clownfish
1 Azure Damselfish or 1 McCasker's Flasher Wrasse
1 Yellow Clown Goby
1 Orange Spotted Goby
1 Red Fin Fairy Wrasse
Inverts-
1-2 Feather Duster(s)
4 Nerite Snails
4 Bumble Bee Snails
4 Dwarf Red Tip Hermit Crabs
1 Randall's Pistol Shrimp
Corals-
1 Toadstool Mushroom Coral
1 Blue Cespitaria
1 Thick Finger Leather Coral
1-2 Candy Cane Coral(s)

 

I thought of Wrasses but they can be aggressive to corals and inverts I read. The snails are going to be Nerites. I like the Azure and I have looked into them, from what I read they are the most peaceful Damsel and will not start fights but will not be bullied. Also for the equipment I changed some things and added others,
I will get a RO System
The Filter will be a Fluval 70
The Skimmer will now be a Aquatic Life instead of Innotive
I will get a Hydor Koralia Evolution 750-850
Should I change anything or is it all fine?


It says on your link that the wrasses might eat feather dusters and snails. I like the Mckoskers Wrasse.

Forgot to ask, would a Candy Cane Coral be okay, I have read mixed reviews on their care and compatibility.

Would this stock work? Tank is 48"x12"x16"
Fish-
2 Ocellaris Clownfish or 2 (A. polymnus) Saddleback Clownfish
1 Azure Damselfish or 1 McCasker's Flasher Wrasse
1 Yellow Clown Goby
1 Orange Spotted Goby
1 Red Fin Fairy Wrasse
Inverts-
1-2 Feather Duster(s)
4 Nerite Snails
4 Bumble Bee Snails
4 Dwarf Red Tip Hermit Crabs
1 Randall's Pistol Shrimp
Corals-
1 Toadstool Mushroom Coral
1 Blue Cespitaria
1 Thick Finger Leather Coral
1-2 Candy Cane Coral(s)

Some of the larger more aggressive wrasses (ie Thalassoma) can definitely be aggressive and are a gamble with reefs. There are however many smaller generally peaceful wrasses that don't bother corals or inverts (ie Possum/Pygmy Wrasses, Flasher Wrasses, Peaceful Fairy Wrasses). Halichoeres (ie Red Lined, Melanurus, Christmas) can munch on smaller inverts, but will leave corals alone. Given the size of your tank the Flasher Wrasses will be the best bang for buck type wrasse you can get. Very Peaceful to other types of wrasses (although it may fight with it's own kind, think Male Beta Fish). The one word of caution I would offer is DO NOT MAKE THE NEWBIE MISTAKE OF GETTING A 6 LINE WRASSE!!!!!!!!!!!!!!!! Many of people are suckered in by it's color and pest killing abilities but fail to see that they are known for snapping and going on killing sprees once they mature, very difficult to trap and remove and they will likely harass/kill any addition you attempt to make afterwards. I know a guy who services other people's fish tanks and he has routinely stated that he has had to trap and remove the 6 line more than any other fish for the aforementioned reasons and had to do so in tanks all the way up to 250 gallons in size. There are no shortage of complaints about them and a quick google search will confirm that.

As for the skimmer, the only HOB Skimmers I recommend are either the Reef Octopus Classic 100 or the Eshoppes PSK-75H or PSK-100H models. Cheap skimmers don't really give you enough benefit to be worth the expense.

As for the Wrasse, it's only the Red Lined where the Featherdusters, Snails are at risk. The Flasher Wrasses (ie McCoskers and Carpenters) would be fine with them.

 

So would the McCosker's and Red Fin be ok with the rest of the stock if I got rid of the Damsel?

 

The McCosker's and the Red Fin Fairy Wrasse should be good co-existing, although it might be wise to add them at the same time just so you avoid the established wrasse vs the new guy type situation. Definitely ditch the Damsel and I would add the clownfish last since they can become super territorial once established (even known to sometimes bite their owners when they are cleaning the tank).

 

Ok will do, but which species of Clownfish do you think would be best?

 

Any of the Ocellaris or Percula varieties. Don't bother with any others as they are too aggressive.

 

Sorry to ask so may questions, but do I need both the API Saltwater Master Test Kit and API Reef Master Kit or just one of them?

 

Sorry to ask so may questions, but do I need both the API Saltwater Master Test Kit and API Reef Master Kit or just one of them?

Neither. I strongly recommend avoiding API for saltwater and going with either Red Sea or Salifert. API is a joke for nitrate testing, can give false positives for ammonia and is the only kit that doesn't use screwtop lids. This means you get nasty caustic chemicals splashing on your hands as you shake them. Here is a good vid on the merits of the Red Sea test kit:

 

So here is my shopping list, tell me if I should change anything. Almost everything is coming from Liveaquaria, Amazon, Chewy, or my local LFS.-
-Equipment-
Current Hood or a Koval 48" LED
Aqueon Pro Heater 200 Watt
Topfin Digital Thermometer
Fluval 70 Gallon HOB
Hydor Koralia Evolution 750-850
Aquatic Aquatic Life 115 Protein Skimmer or Instant Ocean Sea Clone 100 Gallon Skimmer(Is it safe to have a larger Skimmer?)
Instant Ocean Testing Hydrometer
Aquatic Life RO Buddie 4 Stage
Red Sea Reef Foundation Test Kit
-Medicine + Food + Salt-
Instant Ocean Reef Crystals
API Marine Melafix
Probiotic Marine Formula
Kent Marine Purple Tech
Fluval Bugbites Fish Granules
Red Sea Reef Energy AB 2 Part Coral Nutrition
-Rock + Sand-
40 lbs CaribSea Arag-Alive FijI Pink Live Sand
40 lbs Natures Ocean Base Rock
-Fish-
2 (A. ocellaris) Clownfish
1 (C. rubripinnis) Red Fin Fairy Wrasse
1 (P. mccoskeri) McCosker's Flasher Wrasse
1 (E. stigmatura) Tailspot Blenny
1 (G. okinawae) Yellow Clown Goby
1 (A. guttata) Orange Spotted Goby
-Inverts-
1 (A. randalli) Randall's Pistol Shrimp
1-2 (S. sp) Feather Duster
4 (N. sp) Nerite Snails
6 (N. sp) Nassarius Snails(Decided they would be better for the tank than Bumble Bees)
4 (C. sp) Red Tip Dwarf Hermit Crabs
0-1 (T. sp) Burgundy Sea Star(Would it be safe for my tank?)
-Corals-
1 (S. sp) Green Toadstool Mushroom Coral
1 (C. sp) Blue Xenia/Cespitaria
1 (C. furtcata) Candy Cane Coral
1-2 (B. sp) Starbursts Polyps

 

If you got the money and lazy you could get the hannah digital test kits super easy to use also you don't want to completely over skI'm your tank your corals need some of thoose nutrients to thrive

 

For the most part it looks good, but I would definitely change a few things:

1) I would swap the light fixture for a pair of Chinese Black Boxes. It is more expensive, but you can't go cheap when it comes to lighting for corals (trust me, I tried with my first tank and lost several frags)

2) I would bump up your flow in that tank quite a bit. I ran a Hydor Koralia 3rd Gen 1950gph in my 36 gallon bowfront and it was just about right

3) As mentioned in a previous post, if you are going to go with an HOB Skimmer I would stick with either the Eshoppes PSK-75H or PSK-100H, or the Reef Octopus Classic 100. The cheaper skimmers just won't do as good of a job and if you get one you might as well get one that does the job as well as possible. The skimmers you mentioned are generally considered marginal in terms of their effectiveness.

4) I would skip the meds stuff for now. You may never need some of that stuff and it would be better for you to see how the corals do before you start dosing a bunch of different stuff. As for food, I strongly recommend going with Frozen Foods and something like LRS Reef Frenzy (it's possible you can get it straight from your LFS). It is a sort of all in one diet for fish, corals and inverts and is one of the cleanest food sources for your tank (aren't loaded with a bunch of nasty fillers like most other foods which produce excess waste).

5) I would switch the Nassarius snails out for 1-2 Fighting Conch snails. Far more effective at cleaning the substrate and have a wider variety of diet, are more visible, hardy and just plain interesting to watch.

Oh and here is the LRS Reef Frenzy with a full list of everything it has in it:

 

Won't the Conches move the rocks and coral? For the lighting you showed it would cost $320! Also I can't hang any lights. So upgrade the Powerhead to about 2000-2500 gph and get a reef octopus skimmer. What other types of skimmers are there besides HOB? Thanks for the help.

 

Nope, the Conches aren't strong enough to move the rockwork (I think you are confusing conch snails with Turbo Snails) and they generally don't spend much time in the rock work. As for corals that is easily solved by gluing them down and I have NEVER seen one of my conch snails bother a coral.

As for the lighting, a pair of basic chinese black boxes would be roughly $200 combined plus mounts. I don't think you really have any idea at how expensive a decent light for corals are on a 4 foot long tank. I have a 90 gallon that is 4 feet long (albeit much taller and a bit wider) and I have a pair of AI Hydra 26HDs on a rail mount above my tank (in the top 5 for best LED reef lights out there) and I spent $750 for both lights combined and the rail mount (and that was a good price). The Gold Standard (Ecotech Marine Radion XR30 Pros) would run $1600 for a pair plus the cost of a $100 controller and mounts. So believe me, $200-$300 to get a decent LED setup for growing corals is NOTHING. The next step up (ie Ocean Revive T247B or AI Prime HDs) would put you in the $400-$450 range. For reference I made the mistake of doing my first tank with an Aqueon Modular LED and with the fixture and the blue bulb I added to it I spent around $75-$80 on it. What happened? I lost 3 Zoanthid Frags, a soft leather mushroom struggled to survive (and ultimately didn't make it) and it did okay (not great) with a couple of Euphyllia Frags long term. Those Euphyllia Frags are now much happier in my current tank under lighting that is significantly better.



As for Skimmers, HOB are really the only option unless you are doing a sump (secondary tank that your main tank drains down into).

 

I was considering doing a 10 gallon sump, would that be better than just a display tank?

 

I was considering doing a 10 gallon sump, would that be better than just a display tank?

No, generally speaking any sump of less than 20 gallons isn't worth it for the following reasons:

1) You won't get enough extra water flow/volume to make it worth it

2) A solid return pump and protein skimmer are crucial components to a good sump setup and they won't fit in a small tank

3) All sumps and equipment in sumps require maintenance and believe me when I say that you don't want to have a small cramped tank to work in and around equipment in


Adding to this issue, you will need extra equipment that will drive up the cost of your setup (ie In Sump Protein Skimmer, Return Pump and an overflow box since your tank probably isn't drilled with an overflow). Don't get me wrong, sumps are great (I run a 29 gallon sump on my 90 gallon) but on a 40 gallon you can get by without one and it will keep costs down. IMHO the tipping point for sump is about 55 gallons.

 

I have a wet dry filter on my 36 freshwater, would that be a better options? It is16 gallon. Would I need 2 or 3 Phlizon lights, description says coverage area of 36"x36".

He for the powerhead, will the Jebao OW-25 work, says it goes up to 2245 gph.

 

I have a wet dry filter on my 36 freshwater, would that be a better options? It is16 gallon. Would I need 2 or 3 Phlizon lights, description says coverage area of 36"x36".

Stick with the HOB as it will be the most cost effective and useful option. As for the Philzon lights, 2 will be plenty on a shallow tank that is 48 inches long.

 

Will do, thanks for the help!

Hey will the Conch not get too big, it gets 4".

 

For a 48 inch long tank it will have plenty of space. It's only a 4 inch snail (mine are actually around 3 inches).

 

Thanks.

Hey saw a Falco's Hawkfish today and is there any way in my stock that I could get one, like trade the Red Fin Fairy Wrasse or the Feather Dusters?

 

Hey saw a Falco's Hawkfish today and is there any way in my stock that I could get one, like trade the Red Fin Fairy Wrasse or the Feather Dusters?

well hello but really I wouldn't as those guys can be a 50/50 as I mean I've never had one but I have wanted one reasons why not to
cons
1) they can get aggresive
2) they can be picked on with your selection
3) nitrates and ammonia they produce as they eat alot
pros
1) will eat almost anything you give them
2) They don't pick on corals
3) they can be a showpiece of the tank
so personally I would not but if you want it go for it but watch for your levels

 

Thanks, I decided against it because I also heard it was 50/50 but that it would be the one picking on my fish.

 

The other thing is that they could make a meal out of your gobies if they are smaller when you get them (there is a reason why they are called hawkfish). I agree that I wouldn't go with one. They are considered with caution for reefs but with a 48 inch long tank, you could try a pygmy angel:

 

I like the Cherub, but don't Angels eat coral, that was the original reason I avoided them.

Would a BanggaI Cardinal work instead? Or a Yellowhead Jawfish?

 

I like the Cherub, but don't Angels eat coral, that was the original reason I avoided them.

They can, but pygmys tend to be a bit better about not eating them. What I recommend with Dwarf Pygmy Angels to ensure increased chances of not having a coral nipper, is to wait until your tank starts getting some algae growth and then add them. This gives them algae to graze on and then supplement with a bit of Seaweed/Nori. It has the added benefit of being the last fish you add to your tank as they can be a bit aggressive, but in a 4 foot long tank they should do pretty well. I have a Coral Beauty Dwarf Angel in my 90 gallon and he is pretty well behaved. Once in a blue moon he will take an exploratory nip at my coral, but he doesn't like it much (spits it back out) and the coral just grows back and keeps growing. It's the repeated nibbling that is the concern.

As for the Cardinalfish it should work, although over time the clowns may take exception to it going into their territory. The Yellow head Jawfish would be a great choice, you just need to make sure they have at least a 3-4 inch sand bed to burrow.

 

I was planning on doing around 4 -4 1/2" sand bed. Would the Jawfish be fine with the Gobies and the Blenny, I was going to have a larger heap of rock with caves in it and a couple of tunnels, then have rubble and shells around the base so that the tank was split in a half with open water for the Wrasses and sand sifters and a area for fish that like to have multiple retreats.

 

That could work, although the sandbed might be a bit deep at over 4 inches. I would say that would be the max to ensure it can get aerated properly by your sand sifters. Your plan for aquascaping sounds like it would work. Just be sure that there is space for that wrasse to have the full length of the tank to swim. My rockwork runs the length of my tank but it's set in the middle with open space in the front and the back.

 

I was going to have about 4" of room in front of the rock works so the tunnels are large but there is still room for the fish to swim in front of the rocks.