What should I name my Firefish instance

I run a server https://calckey.world , which used to be CalcKey, but the software was re-branded to Firefish. Unfortunately, firefish.world is taken. What domain should I use for my new Firefish instance? Preferably a .world domain.

I have remembered these options suggested to me so far:

• dartfish.world (a sort of fish similar to the firefish)
• fedifish.world
• fire-fish.world
• f-fish.world

Any other suggestions? Or do you like one of the above?