About

River Tank Setup is about aquariums that look and work like a real stream: moving water, smooth stones, driftwood, and the fish, crabs, frogs and small reptiles that can share one tank. We also cover ripariums (tanks where plants grow with their roots in the water) and the freshwater basics every keeper needs: cycling, water testing, quarantine and choosing tankmates.

Who writes it

I'm Jack. I've had fish tanks since I was a kid. When I was about 20, a new kind of tank came out: the River Tank EcoSystem by Finn Strong Designs. It was a kit that fit inside a regular aquarium. A pump at the bottom left sent water straight up, a channel carried it across to the highest pool on the right, and from there it cascaded down through three pools back to the left, where it was pumped up and around again.

I bought the X-Large kit (the RTK-XL, the biggest one they made at the time) for my 55-gallon long tank, because it fit perfectly. What I loved was that it wasn't just a fish tank. Fish, little crabs, small turtles, fire-bellied frogs and even chameleons could all live in the same tank, in the water, on the ledges and in the plants. It was fun to watch and nothing like a plain old aquarium.

One lesson I learned fast: swap the light kit on top for a full screen lid that covers everything. Crabs can get out of just about any tank, and so can some of the reptiles.

Photo on the original River Tank Systems box: the Extra Large kit, model RTK-XL, installed in a long aquarium with plants above and pools of water and fish below — From my original box: the Extra Large kit (RTK-XL), shown here in a 135-gallon tank. Mine went in a 55-gallon long.

I kept that tank for years. I don't have one anymore, and as far as I know Finn Strong Designs is long gone, but these tanks still get me excited. My original owner's guide is scanned here for anyone who still has one.

The River Tank EcoSystem RTK-XL owner's guide cover and the assembled view of the X-Large kit — My original River Tank EcoSystem owner's guide (1995, model RTK-XL): the cover and the assembled X-Large kit.

How we write

Plain answers, checked against good sources, with no padding. When a fact matters (a temperature, a water reading, a species' needs), we check it before it goes up. If something here is wrong, tell us and we'll fix it.

About the pictures

Some photos come from Wikimedia Commons and other free libraries and are credited on each post. Some illustrations are AI-generated to show a setup or a species clearly.