Dalmation Molly nipping large Comets...

Question
We have a male Dalmation Molly who recently started nipping at two 4 inch
long Comet goldfish.  He incessantly nips at their backs.  They dart away but
he follows to nip more.  We've isolated him in a floating breeder, and started
feeding him bloodworms, but need a better solution.  We have another
dalmation but are not sure if it is a male or female..it stays nearby the
prisoner.  Other tank mates are 2 danios, 2 corys, 2 upside down catfish, 2
ghost fish in a 20 gal Jebo tank with a heater. We don't really want to get rid
of him, but the goldfish come first.  Will the nipping hurt the goldfish?  He
doesn't bother their fins - just their backs.  Would more female mollies divert
his attention or are we at capacity?  thanks for your help.

Answer
Hi Jennifer, sorry to hear about that...
What you've encountered is a common problem. For some reasons livebearers such as mollies like to nibble at the slime coating of other larger fish such as goldfish. The nipping not only aggravates the fish, but it can irritate their skin and possibly encourage infection or damage if the nipping is allowed to persist. There's not much you can do to prevent this but to keep livebearers away from goldfish. You might could try keeping more female mollies for him to maybe divert his attention. You could always try that - but I can't guarantee it will work.

Unfortunately this is why goldfish do best in their own aquarium living with other goldfish only.

Best wishes and I hope this helps!
Karen~