South American Blackwater 20 Gallon Tank 

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MacZ

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Hello everyone!

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This is my 20 Gallon Blackwater setup. I'm not completely new to the hobby, but it has been some time since I had to give up my last tank before this one.

Details (sorry, I'm European, so I can only give most measurements in metric):
Model: Superfish 80 Home (not perfect, but best choice for what I wanted, and I knew I'm gonna mod some things.)
Dimensions: 61cm long x 31cm deep x 45cm high
Filter: AquaFlow 200 (downsized from 300 because the current was too high for the fish even after doubling the length of the spraybar and turning it to lowest flowrate.) with biomedia, filterfloss and sponge. Took out the activated carbon the manufacturer puts in there.
Heater: Eheim Jäger 110watt
Lighting: 14watts LED as was in the set. Mostly set on darkest setting.

Hardscape:
4 pieces of spiderwood, 3 random rocks, common sand as substrate.
Good handful of leaves, half cattappa, half native trees from the backyard.
You can count the fake Vallisneria in the corners as well. As I had to get rid of snails right of the start I'll only get real Vallisneria as soon as my LFS can quarantee there's no more snails in their sales tanks.

Actual plants:
3 pots worth of Anubias var. nana, that have developed really nicely I think.
originally 1 Cryptocoryne, but it didn't do well in the blackwater with the lighting so I gave it to a neighbour in exchange for the tetras.
one pot worth of Dennerle Limnopodium (amazon frogbit), that has already doubled.

Stocking:
- 3 quite old cardinal tetras. Neighbour had them in a far bigger tank for 3 years, but his newly introduced CAE picked them off one by one. Had only 3 out of 10 left, when he gave them to me.
- 5 younger cardinal tetras, likely not wild caught, as one has a slightly deformed spine.
- 5 Otocinclus sp., likely macrospilus, but I'm not quite sure. Glad 5 out of 6 made it to the one month-mark. They mostly go for the omnipresent biofilm and leaf litter, but I also feed them organic cucumber, zucchini, brokkoli and lettuce. I DID NOT put them in to control algae, I think in such a biotope they need to be there and I always liked them. Still, 24h after putting them in there were virtually no algae left and there are still no algae in that tank besides some diatoms here and there. Thankfully most have nice little round bellies, none is overly thin.

Thinking of adding some corys OR 1-2 centerpiece fish in there, but no concrete planning for that yet.

Water perimeters:
Temp: 26°C (78°F)
pH: 6.8
Nitrate: ~20-25 ppm
Nitrite: 0.0 ppm
Ammonium: 0.00ppm
general hardness: 9-10° GH
carbon hardness: 6° KH
chlorines: 0.0

They don't add chlorines to the tap water in Germany, but the piping in the house is at least partially copper, so I use water conditioners (aquatan & aquatan blackwater) with the water changes.

Comments, advice and ideas are very welcome! :)

So long,
Mac

Edit: It's up and running since Sept 20 this year.
 

jake37

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Have your anubia grown much ? Even with CO2 (which I started about a month ago); i only get one leaf every 3 or 4 weeks if i'm lucky. Well one of them has actually started to grow a bit faster. The coffee are doing a bit better. My oldest plant is about a year old (started a tank then moved about 6 month mark and took it with me along with some fishes).
 
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MacZ

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Yeah, I have two small runners in 2 month now. No CO2, no vertilizer whatsoever. Could be because of the biofilm on the wood. I suppose they first invest energy into rooting on their surface, but honestly, this is my first tank with plants and my first tank since 2003. Before that I only had Mbuna and other rift lake cichlids without plants.
 

angelcraze

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Looks awesome! Nicely thought out too! That's normal for anubias, 1 or two leaves per month, they are very slow growers.
 
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angelcraze said:
Looks awesome! Nicely thought out too! That's normal for anubias, 1 or two leaves per month, they are very slow growers.
Thanks! I spent a few years preparing to get back into the hobby. A lot changed since back then. :D

I'm in general very happy with the tank. But a few things went wrong at first. The current was to strong at first, which let to the tetras gathering in a too small current-free zone, which led to aggression and stress, which was followed by, guessed it, ich. Lost no fish to it thanks to quick diagnosis and medication. Current problem solved parallely. Some time later one Oto seemed to have a nipped dorsal fin that got infected. While I was still trying to get a half-descent look at it which took me two days at that point, it went missing. Not the first time an Oto hides so well you can't find it, also they really liked to sit in the leaf litter, that was at that point already pretty much mulch. 2 days later I did a water change and a partial rescape and found it dead under the wood.

I think my biggest mistake with the otos was simply changing the hardscape only 3 weeks after adding them. Before that my greatest concern was with the cardinal tetras that were fighting all the time. I put one piece of wood to the opposite side of the tank and laid another branch across, aswell as pulling out the Cryptocoryne for my neighbour, while I added the fake vallisneria to give the otos more hiding spaces, since moving the wood and removing the one plant actually limited their hiding spots. It definitely helped the tetras give them more structure to build their little territories. Since then the otos on the other hand stay only on the darker side of the tank and stay in their group schooling in the corner while the tetras stay on the other side shoaling between the roots and in the open water. At least the otos are out and about instead of hiding away. Maybe I should have bought 10 instead of six, but now the shop I got them from already got a new batch in that doesn't look very healthy and I won't let another Oto die here except of old age. As they still seem to eat and be well fed, I'm not too concerned to bring the rest through until they're fully stable again, but yeah. Mistakes were made.
 
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Update:

The bladder snails seem very much eradicated. Seen and removed one earlier, but haven't seen any in a week.

Otos still in that upper corner, O2 is fine, no biofilm on the surface, tried some new veggies tonight, they like it very much.
It's a kind of lettuce that looks a lot like spinach but isn't. Don't know the english name of that stuff. I see three of them on it right now. Wow! Within a few minutes.


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angelcraze

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Nice! Thanks for the tips on feeding :) It might be kale or collard greens. They are some of the more nutritious veggies, they have a lot of calcium for invertebrates (like snails haha) to keep their shells strong. You just weighed the leaves raw (without blanching) at all? I might try it with my plecos.

I found it really difficult to get ottos to eat something besides biofilm and algae, so your info is helpful. My mom's ottos eat mushrooms....go figure.
 
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MacZ

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I looked it up. We call it "Feldsalat" (litteraly "field salad") which is known in English as "cornsalad". Most common salad green here besides eisberg and common green lettuce. Never saw it overseas. Mushrooms... hm... no bad idea actually.

Anyhow, I blanched it for a minute in boiling water then put it in cold water (not ice, but as low as the tap goes), bundled it with a rubber band and weight it down with a stone.

You're welcome! Hope I could help. :)

Maybe you've seen my question about groing out angels in that tank for a while. Any suggestions?
 

angelcraze

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Oh thanks for letting me know about the blanching, they still looked fresh. Good to know, I like the idea :)

I haven't seen your angelfish question yet, but I will look for it ;)
 

DoubleDutch

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Looks great.
 
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MacZ

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I'll just ask you here, so I can find it myself: :D

The neighbour I'm working with wants to re-vamp his tank (ca. 300litres) and can't afford Angels the size of those he already has (project is expensive enough as it is.), so we were pondering if I could keep some smaller ones (2-3) for a few months in my tank to grow them out a bit. After quarantine that is. The quarantine tank is a 40 litre/10 gallon, that is not yet up and running, which would be obviously too small for longer than the quarantine.
There's plenty of planning time, since we won't go for it sooner than the end of January.
 

angelcraze

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MacZ said:
I'll just ask you here, so I can find it myself: :D

The neighbour I'm working with wants to re-vamp his tank (ca. 300litres) and can't afford Angels the size of those he already has (project is expensive enough as it is.), so we were pondering if I could keep some smaller ones (2-3) for a few months in my tank to grow them out a bit. After quarantine that is. The quarantine tank is a 40 litre/10 gallon, that is not yet up and running, which would be obviously too small for longer than the quarantine.
There's plenty of planning time, since we won't go for it sooner than the end of January.
Lol, I already answered in the other thread!
Ok copied and pasted
I would go for it. Your tank is almost 18" high which is a nice tall tank for angels to grow up in. I would not keep it blackwater though, because growing angels require lots of water changes to grow out nicely, especially if the tank is smaller. I want to keep my nitrates below 5ppm in grow out tanks.

You might see issues with one becoming alfa and one being the one always bullied if they are there long enough to mature, so ok for young angels, not ok for young adults. I always say 3 is not a good number for cichlids, but it might be better with 3 or 4 growing out together. Problem with that is they will outgrow the tank sooner.

I still have used a 29 gallon before for growout, so don't see a problem. You just have to kind of know when it's time to move them and don't keep them there longer. Also be prepared to have to change water everyday. That's my suggestion ;)
 
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Thank you so much!

Yeah, I thought so already with the bullying. First tank ever right now without cichlids. We want them to a half descent size before they go into the 100gal. We were thinking to start off at 2.5'' (hight dorsal-analfins) and grow out to 5-7''. They should be big enough then to hold their ground in the other tank.

The idea was actually that they could already acclimate to blackwater here, because the other tank is also going to be one, too.

Keeping nitrates below 20 ppm is hard enough (today's reading was uncomfy 25ppm, but tomorrow is water change-day). Daily water changes is hardly possible, also I think that would stress out everybody in that puddle of a tank too much. I have a part-time job as a teacher and doing graduate courses in university, so I'm often out of the house for 12h+. Most I could do would be twice a week. The system is actually pretty stable in general, I could warp the filter somewhat to compensate, but that's all I can think of right now.
 

jake37

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I'm growing 4 angels out in a 20L - they are just approaching quarter size and bicker a bit - they never hassle anyone else in the tank but they bicker with each other all the time esp when i'm feeding. I'm also growing 4 more out in a 29 (which is a lot taller). They bicker but not when i feed them - they are a bit bigger than the ones in the 20L (maybe 1 month older). Bit concern about the ones in the 20L - i had planned for the ones in 29 to form a pair then move the ones in the 20L into the 29; and the pair in the 29 into the 120 (extras go to lfs).
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Anyway you didn't say what size your angles were but if they are nickel size (which is not uncommon around here) they should be fine in a 10 for a couple of weeks for quarantine. If they are quarter size i'm not sure there will be enough room for them to get away from each other (here is a picture of my 20L to give you a sense of things):
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I think the 10 is the same height as the 20L - also i have a bit with them (2 guppies; 10-15 pygmy cory; and a clown pleco i haven't seen in 2 weeks). The nitrate in this tank stays lower than it should (sub 10 probably around 5 - no clue why so low). The two in the middle are the big 'fighters' they never stop - with the blacks in the 29 they fight a little but never when i'm watching - they wait till i walk away.
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Thanks! I have to ask you because I'm not sure I understand all the numbers. (I speak quite fluent English for a non-native speaker, but I'm used to the metric system.) 20L = 20 (gal) long or 20 liters? And the rest is also gallons, I guess?

Well, I said what size we'd like to start with (fin-span top-bottom 6''), but there are none yet. Earliest start-date for the project is mid-january. Last time I was in the US was 20 years ago, haven't seen a nickel or quarter in RL since. :D
They usually are found in shops here at about 2.5'' fin-span smallest, then 5-7'', then fully grown and the prizes rise accordingly. Medium-size (our grow-out goal) of about 6'' cost 50 bucks (55US$) a piece at lowest at chainstores or online retailers, and up to 75 in the LFS, that would blow up the budget of my buddy too much. The small ones, excellent quality and health start at 15 at the LFS. So even upkeep-cost included for the grow-out, we'll be at least 100,- below store-prize.

So you say quarantine in a 10 gallon is rather not a good idea? Not even two weeks?

Before you ask: We don't mail-order here, there are 4 stores within 2miles and even in the country-side people rarely have to drive more than 30min to the next store. And I'm talking LFS, not Petsmart or the like.

Also, what do you think? How long would it take the angels to grow to that size?

I know with the current stocking, I'll have to delay getting corys until the angels are out. I want to roughly plan when to get my corys and into quarantine, so I can basically switch out angels for corys in one go.
 

angelcraze

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I don't know about growing them out to that size in the 20 gallon. I do think you will run out of space and they will fight. I had two survivor baby angelfish grow up together, but I had to separate them at about 6 months. The bigger one (male) was chasing the smaller one and being too aggressive. Twice a week water changes is better than nothing, but it's been my experience that growing angelfish really need good fresh water to grow out to their full potential.

When you said "grow out", I thought you were going to dedicate your tank to a growout tank and not grow out angels in your community tank. How much water do you change at a time? I'm sorry, but I wouldn't do it if you can't change much water :( But I'll tell you, I am changing 50% water every 2 days in my angelfish QT tank, I have catappa leaves on the bottom and water is still stained.

Angelfish are different than other fish that end up looking pretty much the same no matter what. I look at angels more like discus because how they are raised really matters for overall health and appearance. I'm not going to lie, it's a lot of work to grow out beautiful angelfish, guess that's why they are so pricey. If they fight, they can permanently damage fins, if they are too cramped, they will often have bent fins. If they don't get enough fresh water, they can be stunted.
 

jake37

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My numbers were gallons. In the US small angels are usually around $4 - big ones can be expensive (depends on type). I found for my first pair it took around 9 months from birth to nearly full grown (I purchased them at 3 month) . I'm new at this but been buying them around 3 months old when they are around 1 to 1.5 inches i guess. So for me it is 6 month project. I guess angels are cheaper in the US - the last set cost me $20 for 8 angelfishes (4 platinum and 4 blacks). Right now I am exceptionally happy with the platinum but i do worry the 20L will stunt their growth. As I said I hope to move them into the 29 as soon as the black forms a pair.
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As to your specific question I'm not sure how many angelfish you will buy - if you will buy 2 6 inch angels that is a pair a 10 might be ok for 2 weeks and certainly if they are small. But if you buy a group (4 to 6) of unpaired angels - if they are small 1.5 inch - 3 cm - I think it would be fine for 2 weeks but if they are 6 inches they will kill each other at least that was my experience. I started with 8 in a 120 gallon tank and they were fine from age 3 to 8 but then as soon as a pair formed they killed the others. It took a month for an actual kill - they started with a bit of fighting and then chose opposite corners but slowly the pair decided that the other corner was not ok for the angel to hide and chased them down (the story is not complete because when the pair formed i removed a few and they only chased down the remaining ones).
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Anyway my plan is to move the ones above into a taller tank when they are around 6 months old and I think they are around 3 to 4 months old now but sometimes plans dont' work. If i have to move them sooner i will try the 120 and do something with the pair currently in the 120. The smaller of the pair in the 120 would probably fit in the 20 - she is a lot smaller than the bigger one. The bigger one is too tall for the 20L (in the us there are two types of 20 gallon tanks a 20H (or standard) and a 20L which is longer and shallower. The 29 gallon tank is the same length and width as the 20L but taller. This is the first time i've put angelfishes in a 20L and from the picture they seem to have plenty of room as this age - 2 are in each of the far corner and the two in the middle like to bicker but they have lots of room above and below - I think things will change when they get older.
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I tend to do water changes based on nitrate level. As long as nitrate stays below 20 I will water change once every 3ish weeks. I'm feeding them 3 times a day because they are small but as i said for some reason in that small tank so far the nitrate level hasn't move much - in my larger tanks the story is different and the nitrate gets up to 15 or so in 2 weeks (i have a 29 with guppies and a 29 with 4 black angel and 6 white fine rosy tetra). I'm pretty new at this so i might be making mistakes so don't trust everything i say.
 
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Ok, if I understand you both right I take the following things from your posts:
(and sorry, I'll go by cm now, inch confuse me too much)

- 10 gallon for 2 weeks quarantine would be okay for 2-4 angels at 3cm, but not for longer. My thought, too, so here we're on the same page.
- the 20 gallon would work for them up to 10-15cm (That's the goal and then "Out of my tank you little punks!" I'm still talking hight, so length would be at around 6-7cm, right?), IF it's a dedicated grow-out-tank. So if I can't relocate my own fish for the time being, that's not an option. I guess not even for 2 specimens.

Well, guess then I'll have to tell my buddy we'll rather have to invest into a bigger quarantine-tank that he can use for the grow-out after his main tank is re-vamped and all the other stock intended for our respective main tanks is out of quarantine.
Or he takes the risk of adding 2-3 mid-sized, expensive ones directly to his main tank. Still too risky for me, but his decision, then.

The "use my tank setup for grow-out"-idea is scratched then from my side.

Thanks a lot for the info, guys, really made me realize that I should not take risk and work on my part in this case. :)

Which brings me to my other question then:

Any ideas for completing my own stocking? Right now it's 8 cardinals, 5 Otos. I'm thinking either corys or a centerpiece-fish. Just a few conditions: South American, Blackwater, small enough for a 20 gallon, no jumpers (because I have to leave it open during spring/summer.)
 

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For small tank scavenger I like pygmy cories; and/or kuhli loaches. For kuhli 4 or 5 - for the cories 8ish. The cories are really small and kind of interesting. Mine form up in groups of 4 or 5 and swim mid tank at times - though they also spend a fair amount of time hiding. kuhli are unpredictable - they also get quite a bit larger. When you buy them they are usually fairly small (not that thick around) but my older ones have put on substantial mass - but it takes a while - in the 29 they are approx 4 months old and are not much thicker than 1/4 of an inch - but in the 120 i ahve some a year+ and they look substantially larger - max length tends around 4 inches. I can never predict if they will hide for months without being seen or spend months glass surfing. Right now the ones i have have gone into mostly hiding mode (in the 29 i know where they hide and are mostly easy to find but in the 120 where i have 10 or 11 - i might see them once a week (a while ago they spent 2 months glass surfing and then poof gone with the wind - maybe it was time of year - not too sure as i've not have them 2 years yet).
 
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Kuhlis are out because South East Asian, although I like them wiggly, but at one point there's too much. :D Also I know they squeeze through the smallest spaces in the lid. That won't work here. If they try to get out I'd have all of them gone within days.

Pygmy Corys were on my list. Until I saw them at the stores. They all have them but only at half the size of my other fish. And especially the cardinals behave like piranha when I'm late for feeding. I'm thinking either C. paleatus or C. nanus at the moment. Or maybe C. hastatus, because their coloration is the closest to my Otos, maybe that could solve any group-size related problems, in case more Otos go the way of all earthly beings.
 
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