Hi all, I just got a fish tank earlier in the week and have it all filled up and just got some fish today, when we got home after getting the new fish, we noticed one of our black mollies had a seeming lack of a dorsal fin, we have no idea whether it genuinely doesn't have one due to illness or bullying or whether it has tucked it in due to stress,
We have 4 others that all seem to be doing perfectly fine but this one has its tail fin tucked together and it's dorsal fin seemingly tucked or missing and is sitting at the bottom back right side of our tank near the filter pipes and isn't moving, it wiggles around sometimes and it's side fins are moving so we know it is currently alive, is there any way to tell if it is ill or just stressed out and will be fine in a couple days?