150 gal native river ecosystem tank

Hi everybody. So, I’m putting this in the build forum, even though it’s already been built. It’s still a work in progress, and I’m very open to ideas.

A little backstory: I’ve owned a coral reef aquarium design/installation/management company in Chicago for nearly 20 years. A few year ago, I decided to go into education in addition to the aquarium biz, and am now also a high school science teacher. Being in the classroom has opened up using freshwater systems that my clients typically would not be interested in.

OK, so here is the set-up:

Native river ecosystem exhibit: the idea is to replicate, as naturally as possible, a specific location on a nearby river. All biotic and abiotic elements in the tank collected in a 100m section of river near our place in W. Michigan. The tank is designed to have multiple zones so as to include numerous habitat features (specifically, a log jam in heavy current with a shallow deposit zone). There will be no traditional filtration used. Just microbes and plants.

Species:
- smallmouth bass (5)
- largemouth bass (1)
- black crappie (2)
- rock bass (2)
- brown bullheads (2)
- Johnny darters (4)
- Rainbow darters (4)
- round gobies (2)
- crayfish (4)
- green frog tadpoles (3)
- map turtle (1)
- spiny softshell turtle (1)
- snapping turtle (1)
- Iris sp.
- Valisnaria americana
- Sagittaria latifolia
- some other unidentified aquatic river plant

(all animals young of the year, to be released at end of school year)

Tank- 170 gal (72”x30”x18”)acrylic w/ dual overflows and cabinet stand (was a reef tank; donated to school by a client who was retiring)

Sump- custom acrylic sumps I built for the reef, connected by 1.5” bulkhead. If I recall, they’re both 30”x20”x17”. They are plumbed in but not used for anything specific at the moment

Filtration- nature

Lighting- 1 AquaIllumination Hydra 26, 2 12” Finnex LED…will probably change some of this based on what I decide to with sump.

Heater/chiller- none

Quarantine-

Other- some cheap Vortech knock-off (Eco?) pump to provide the more natural river current

Substrate- sand and gravel collected from river collection site. Shallow end has muck underneath sand, also collected from site

Decor- all wood, rocks, and live plants collected from river collection site

Build details and pics to follow

 

I assume you are going to please us with images.

Seems like a lot of animal species for a 150 (or is it 170) gal biotope.

 

The Early Stages

In order for this system to work the way I wanted it to, there were some design challenges. Here’s a little bit on how I put this together and my (at times ridiculous) thought process.

Challenge #1- how to have a shallow end
I wanted to have a distinct shallow (3-4”) part on one end of the tank. Sure, I could just add like 200lbs of sand and then slope it up toward one end, but that is problematic in a couple of ways.

First and foremost, angle of repose. In order to get a shallow end on a tank that tall using primarily sand, I would need to dedicate 2/3 of the length of the tank to the slope and the shallow end because the sand can only maintain a certain degree of slope without cascading back down. While that could make for and interesting look, it also wastes a lot of tank volume.

The second problem is that if I did go that route, I would have a 2’ deep sand bed and be putting a bunch of effort into essentially building a tank full of hydrogen sulfide.

The third issue is ensuring water is somewhat actively flowing over the roots of the plants to increase NO3 and PO4 uptake. A static bed of sand would be fine for the plants, but would minimize nutrient uptake.

Finally, the water level could not go up to the top of the tank, because I would be keeping the space above the tank open (no cover/canopy) in order to allow plants to grow, sunlight in, etc, and I would be keeping animals capable of escaping. So I needed to have the max water level be ~4-5” below the top of the top of the aquarium.

Here’s how I handled this challenge:



The first thing I had to do was completely cut out one of the overflow boxes. I used a multi-tool, and while it was hardly perfect, I succeeded in removing the overflow without destroying the tank. The other overflow box had to be cut shorter to accommodate the lower water level. Looking back on that part, I should have just used a hole saw to cut openings at the level I wanted. Cutting the top 4” off was…well, the squeeze wasn’t worth the juice.

I then capped the bulkheads on the side the overflow was removed from. I thought about making it so that I could open it up and maybe hook a recirc pump to it, but then considered that if something went wrong, I wouldn’t be able to get to anything from within the tank.

Then I had to create the shallow end. To do this, I used 2 plastic storage crates with the bottoms cut out, and placed each on its side. This created a void space under the shallow end sand bed through which water could be pulled downward through the bed and over plant roots.

Then I used some outdoor paving blocks to create an extension shelf where wood could be mounted on the side facing the front, with a shallow space behind it that would allow relatively fast slow over shallow water for about 12-16” going toward the deep end of the tank.

I also had to add a couple of pavers to fill in the extra space along the front in order to fully support the shallow end bed.

The top of the shelf is plastic egg crate with fiberglass screen zip-tied around it. Wanted sand/substrate to not be able to flow through while water could.

Then to make sure I could keep my sand bed where it belonged, I added some poly-filter pad that I could then seal along the acrylic with Quikrete.



Naturally, I didn’t think to sand/buff the acrylic until all of this stuff was already in the tank.

 

It will be interesting to see how this progresses.

 

Challenge # 2: dealing with sand

Sand is a great substrate for a natural aquarium. Looks great, is dynamic, plants root well in it, and detritus settles on top of it for easy removal…although I’m not worrying about the last part, as I don’t plan on changing any water.

The issue with sand is using it in any underwater application where gravity can act on it. Then it basically liquifies and will leak out of any thing you make that has even a very small opening in it. In the case of this tank, I knew having an elevated sand bad could be very problematic.

To counter that, I sealed all of the spaces around the screen with hydraulic cement. That ensured that the sand I put in the shallow end would stay in the shallow end. The sides and end panel were no problem. But the drop-off was challenging.

This is the final foundation. The piece of wood going diagonally gives me a way to put a gentle slope on the shallow end as well as provide a sort of ‘sea-wall’ to keep that substrate where it should be despite fairly heavy current coming from the opposite end of the tank:



Sand in on the shallow end:



I mixed some garden soil in with the sand. If I had this to do over, I probably wouldn’t do that. I think it provided a lot of nutrients to the plants that I would rather they get from the fish waste etc:



Finally, I decided to take a moon shot on this next part. I really wanted a clay shelf/wall under the wood. I knew most clays would dissolve underwater, but at the same time, the river I collected from has a lot of clay bottom. When I tried to use that clay, it was fairly hard and almost impossible to sculpt. So I used another kind of clay and mixed some sand and hydraulic mortar in:



It almost worked. The clay stayed intact underwater. The problem is that I laid down a base layer over the pavers, and then stuck shelf pieces onto the base. Once submerged, water got between the shelf pieces and the base, and they fell off.

Rather than give myself a perpetual headache to deal with, I drained the tank, scraped and sprayed all the clay off, removed it, and vacuumed the bottom until all traces of clay were gone. I then just put a base layer of hydraulic mortar on the pavers and then placed additional wood on it. To this day, I’m not sure how I feel about that.

There might be some reconstructive surgery coming up during summer break.

Also, you can’t really tell from the pics, but I did end up sanding/buffing the acrylic out.

More to come tomorrow.

 

Just got to say. Nice project but… first you’ve just reduced the size of the tank by about half. All of the bass species will be too big for that tank. The snapping turtle will eat most of the inhabitants including the other 2 turtles. Yes I’ve kept turtles. Snappers eat whatever they can catch. By reducing the space of the tank you’ve reduced hiding spaces.

Now if you remove the soft shelled and the snapper you will do better. Next the crayfish will eat whatever they can catch too and they hunt sleeping things. If you kept the bass they’d eat the crays. To pull off what you’d like to do you’d need a pond of about 1000g.

What I did for turtles in a glass 150 was silicone a plexiglass shelf/island on one half of the tank. Going from about an inch in to 4 inch deep. With the lower end going into the water. Added a piece of driftwood into the tank from the plexi for the turtles to climb out of the water and mounted a heat light about the ledge. This way I still kept most of the water. But I kept no fish with them except feeder goldfish.

 

Just got to say. Nice project but… first you’ve just reduced the size of the tank by about half. All of the bass species will be too big for that tank. The snapping turtle will eat most of the inhabitants including the other 2 turtles. Yes I’ve kept turtles. Snappers eat whatever they can catch. By reducing the space of the tank you’ve reduced hiding spaces.

Now if you remove the soft shelled and the snapper you will do better. Next the crayfish will eat whatever they can catch too and they hunt sleeping things. If you kept the bass they’d eat the crays. To pull off what you’d like to do you’d need a pond of about 1000g.

What I did for turtles in a glass 150 was silicone a plexiglass shelf/island on one half of the tank. Going from about an inch in to 4 inch deep. With the lower end going into the water. Added a piece of driftwood into the tank from the plexi for the turtles to climb out of the water and mounted a heat light about the ledge. This way I still kept most of the water. But I kept no fish with them except feeder goldfish.

Stay tuned!

 

I'm looking forward to additional updates. Thanks for posting in such detail.

 

A little backstory: I’ve owned a coral reef aquarium design/installation/management company in Chicago for nearly 20 years. A few year ago, I decided to go into education in addition to the aquarium biz, and am now also a high school science teacher. Being in the classroom has opened up using freshwater systems that my clients typically would not be interested in.


(all animals young of the year, to be released at end of school year)

Why Release of Captive-Kept Fish is Unacceptable - Conservation and Ethics - NANFA Forum

^^^You should already know this being a teacher and in the biz.^^^
It is unethical to release fish kept captive.
Your stocking is a dream or nightmare if it really happens.
I kept natives [ 2 bass, 2 sunfish, 1 pearch and 2 pickerel] that all enjoyed freshly caught minnows and crays. Hundreds a week!
They started at 3-4 inches [ the pickerel were about 6 inches when caught ] and ended at well over 1 foot in less than one year.
They were kept in a 135g [ 72x18x24 ].

 

watching this thread!!

 

Why Release of Captive-Kept Fish is Unacceptable - Conservation and Ethics - NANFA Forum

^^^You should already know this being a teacher and in the biz.^^^
It is unethical to release fish kept captive.
Your stocking is a dream or nightmare if it really happens.
I kept natives [ 2 bass, 2 sunfish, 1 pearch and 2 pickerel] that all enjoyed freshly caught minnows and crays. Hundreds a week!
They started at 3-4 inches [ the pickerel were about 6 inches when caught ] and ended at well over 1 foot in less than one year.
They were kept in a 135g [ 72x18x24 ].

I have a scientific collectors permit from the Michigan DNR for the animals listed stipulating that the fish are either euthanized or kept. I have no interest in keeping game fish in an aquarium, nor do I have interest in euthanizing them.

My brother has a two-acre pond on his property that does not connect to any waterways. It’s good habitat. Not sure the smallmouth will be able to spawn in there, but otherwise it’s a good landing spot.

 

Just gotta say...this is an amazing project...way over my head but will definitely follow.

Good luck

 

I just realized that I don’t have any pics/vids of the final set-up before getting it up and running, so we’ll have to move right into the results portion of the thread.

Before doing so, I wanted to address a couple of points made by other posters.

86 ssinit pointed out that I had cut the overall tank size significantly with the way I designed it, and I wanted to go into more detail about that:

Zones
I actually increased the size of the tank by creating several distinct zones in the tank. River habitats often have dramatic features as a result of moving water and its interactions with things such as rocks, fallen trees, root structures, and substrates. The idea for the tank came from a specific structure in this particular river: a tree root structure near the bank. I liked it because there was a lot going on in a small space. There was a distinct fast current over a gravel bottom with rocks against one side of the structure, a shallow back-eddy with sand and silt deposits and semi-aquatic plant growth on the back side against the bank, and a really cool undercut.

The shallow end on top of the crates provides the undercut, as it is open to the middle of the tank and animals can go under it all the way to the end.

Then there is the little shallow rip behind the wood structure. It’s about 6” deep with significant flow. Of course, the deep end with bigger rocks and the shallow end are their own distinct zones, as is the face of the wood structure. Providing a natural river current further differentiates the zones. Fish occupy different zones based on where they established their territories.

86 then mentions potential compatibility issues. I intentionally only collect young-of-year animals so that I don’t overcrowd the tank. All bass, crappie, rock bass, and catfish were <3” when collected. The three turtles were also YoY, and <3” shell diameter. Now, to 86’s point about the snapping turtle…it’s the one that I had on probation and was ready to yank if it became a problem. But the snapper is a softy. Shy, and not very aggressive.

Regarding size and feeding: the animals will only be in the tank for a total of 9 months. While there will obviously be growth, feedings are managed to not promote excessive growth. The primary foods are blood worms, mysis shrimp, earthworms, and once a week some minnows and small crayfish.

At the end of the school year, animals are collected and released into the pond on my brother’s property, where they can grow as large as they want to.

More pics/vids tomorrow.

 

I'm not intending to raise the bar. The following tank are Paśnik's, so it doesn't get much better than this anywhere in the world. Just pointing out the number of species you intend to keep. How many inverts and fish can you find in a habitat given 150 gal.

It doesn't have to be that many to enjoy a tank...

The bank of the Solinka river, near Cisna town. Bieszczady mountains. Poland – Biotope Aquarium
The bank of the Solinka river, near Cisna town. Bieszczady mountains. Poland, 225 L – Biotope Aquarium
Meanders of a forest stream, a tributary of the Chodelka River near Bełżyce, Poland, 225 L – Biotope Aquarium (contains a Orconectes limosus)

 

Here are a few pics/vids of the start of the system. There was no cycling period, because all of the substrate, structure, and plants came directly from the river.

A few more things: the idea is to establish as close to a natural ecosystem as possible, so there is no mechanical or chemical filtration used. No medications. No water changes. Just gas exchange using pumps and nutrient control through natural bottom-up and top-down processes. That was always going to be a challenge with just the plant growth within the tank.

When you see the tank, you’ll see 3/4” PVC ending at a ball valve. That is a line coming off the return pump meant to feed a swamp tank that is designed so that in addition to additional plant growth, water moves down through a 7-8” layered substrate bed to generate anaerobic nitrate reduction. I have not built that yet, but I think it’s coming soon.

Unfortunately, a lot of my extra-curricular focus recently has been on the coral reef and mangrove lagoon system, so I haven’t given much attention to the river. But I think I’m going to start to build that soon.

Also, while there are some artificial lights used, the majority of the light going into the tank is natural sunlight. My full length of my classroom is big south facing windows. I’m on the top floor, so there are no obstructions. Where the tank is gets several hours a day of indirect sunlight, and about 3 hrs day of straight sunlight.

So, here is how it has developed.

Early September:

https://imgur.com/a/PDSkCMc

https://imgur.com/a/N6sWhfP

Initial addition of fish, turtles, and plants. The fish had some parasites on them when collected (Chilodonella, black-spot flatworm, flukes, and one had some fungus). I didn’t worry too much about introducing that stuff, as it was inevitable in using water, substrate, plants etc straight from the river. I expected it to clear up pretty quickly.

I really didn’t like the way the shallow ended looked in how you could see the pavers. As if that weren’t enough of a problem aesthetically, the one fish I lost was a smallmouth that wandered back there and ended up getting stuck in the small space between the paver and the acrylic. So I decided to paint over that part with dark pint so that the pavers and pad was covered up, but also so that fish weren’t compelled to venture back there thinking they could keep going.

At this point, I don’t have the current pump added, so the flow is pretty low coming just from the return pump.

 

wow this was a fast build... how did you collect the fish so fast?

 

wow this was a fast build... how did you collect the fish so fast?

It was actually pretty slow. I started it in August, and chipped away at it when I had a little time so that it was up and running when school started.

Animal collection doesn’t take long. I went to the river at night with an aquarium net and flashlight. Pretty easy to catch everything. The turtles were collected during the day. I know where the soft shells lay eggs, so there are always a few 2-3 month olds around.

Since I started it, I drained some water down so that I could change some things around with the plants. That was all I’ve changed so far.

It’s still an active build, because I still have the swamp/bog tank to build, and a 40-ish gallon sump that I want to do something with.

 

Fast-forward to November:

 

Where did you source your Sagittaria latifolia from? Seed or tuber? I was able to get camas last year, but no arrowroot yet for my ponds bog filter aquaponics.

 

Where did you source your Sagittaria latifolia from? Seed or tuber? I was able to get camas last year, but no arrowroot yet for my ponds bog filter aquaponics.

I just dug a plant out of the bottom of the river

 

I don’t exactly like that but I will lol

I should be surrounded by it, but 125 or so years of farming has eliminated them. Oh well, I’ll try my luck at the native plant sales again this spring. Last year I was so excited to find a vendor with Camas and rice root that I completely missed the Arrowroot sitting there (also at the time I was hoping to gather wild) lol

Ain’t science fun? lol I’m doing something similar using endemic PNW species except the focus is on food production. Effectively looking into what might have been had European contact been different. Growing endemic food crops off fish waste, though I am currently cheating a bit with goldfish instead of trout due to current size limitations.

 

OK, so…fast-forward to November. Here’s where we’re at:

https://imgur.com/gTYu3Aa

I’m 99% sure the plants are Iris pseudacorus. As you can see, it’s gone a little crazy. That was early Nov…there’s even more now.

 

OK, so…fast-forward to November. Here’s where we’re at:
View attachment 866958

https://imgur.com/gTYu3Aa

I’m 99% sure the plants are Iris pseudacorus. As you can see, it’s gone a little crazy. That was early Nov…there’s even more now.

Jealous.

 

One of my favorite parts of the system are the turtles. I’ll get more detailed later about the many really interesting interactions between all of the animals, but I just wanted to share some turtle stuff.

The snapping turtle is super shy and spends most of the mid-day hours buried in the sand in the shallow end. This morning, it was out prowling around for food. Pretty rare to see it all the way out in the front:



The stars of the show are definitely the map and softshell. Very different personalities and very different habits. Sometimes at feeding times, they get into minor skirmish. By that, I mean the softshell will bite the map turtle’s leg…for some reason, the map turtle doesn’t seem to care. It just goes right back to eating like nothing happened.

While they do have their moments, and I’ve thought of removing one of them, most of the time they are putting out old married couple vibes. At some point every single afternoon, I see some kind of scene like these:





Sometimes they just cruise around the tank together. It doesn’t seem like they are paying any attention to each other, until you see one change direction and then the other one turns and follows like a puppy. These two are hilarious.