Just to add onto this, Coral Catsharks are typically more comfortable in pairs of 2 or more. They will group up in the wild, and I've never had any issues with them fighting amongst themselves.Shark eggs have a hatch failure rate, so buying newly hatched young is often better. Females are typically larger than males. However, I've had male epaulettes fight. Coral catsharks are better in that regard.
Jay