im new to this site and to keeping fish so bear with me and be patient!
so i started keeping cardinals about 5 months ago, ive tried in the past an never had much luck but this time ive done pretty well as ive only lost one but i think there was something wrong with him from purchase.
i have a small starter tank which is about 18 litres or about 5 gallon roughly i think. i have 6 cardinals and two shrimp. they have been fine and got along well so far until i recently introduced 3 guppies. the cardinals seem to be obsessed with nipping at their tails. it seems to be just one guppy they target but will have a go at the other too occasionally.
im guessing there could be a number of issues..
-is my tank overcrowded? (although i did make it clear to shop what i have)
-is the guppy not well?
-are the cardinals territorial because they been there so long?
the last point of territory is making me wonder as the nipping seems to get a lot worse when the light is turned on?
there is no visible damage to the guppy but i imagine there are not having the best of times in there. unfortunately i dont have a spare tank to separate them atm but im guessing this is an essential i should invest in.
any help you could offer would be greatly appreciated, thanks!