Can Fire eel Live With Zig-zag eel?

These are two spiny eels of near identical build, one reaching a metre and the other 90 cm, and both profiles carry the same warning: keep one per tank, because they can be aggressive toward their own kind, unless you can keep five or more and spread it out. A single specimen of each is close to the arrangement that warning describes.

Water agrees completely, 24 to 28 °C and pH 6 to 7.

If you attempt it, the tank has to be genuinely large, well past the 500 litres either species needs alone, with a deep sand bed for burrowing and several separate lengths of pipe, wood and rock cave so each has a territory it never has to defend. Both are carnivores that swallow whatever fits, so every other tankmate must be too big to eat, and both are notorious escapers, which means sealing the lid at every gap. Kept in anything less, expect one to claim the best burrow and harry the other off its food.