I have a Golden Dwarf in a Fluval evo 13.5 and a snowflake in a biocube 32 (they will both be getting tank upgrades around June). Eels are very messy and add a lot to the bio load of the tank. I have Seachem purigen and Chemi Pure Blue in both tanks. I also spot feed them so I can vacuum out any mess after they're done eating. I do weekly water changes with 5 gallons for both tanks, the eels are doing great! Make sure you have enough rock in the tanks for them to hide in and feel safe!
I should also add that they are alone in their tanks, except the clean up crew, eels can be territorial and I dont want to risk them hurting eachother
