Help! Sorry for the ignorance, but is the long spine on the dorsal fin what is meant by the "filament".
I have 4 McCosker's that arrived today. I asked for one male and 3 juveniles or females. All 4 have a long spine on the dorsal, one is small spine, one medium, and 2 are quite long.
Does this mean they are all males? Can I put them together or will there be a big fight?
They are acclimating now.
Help!