PlanetCatfish.com

Tank: 20 Gallons Long
Planted
9 emerald eyed rasboras, 4 pygmy cories, 4 cherry barbs, 1 amano shrimp, 1 male BN pleco, 1 female BN pleco


Tank has been set up as such for around six months.

Now, I'm 99% sure that my BN plecos are different species. The male, or at least the one I think is a male, has grown many head tentacles, and doubled in size. The female (again, the one I think is female, based on the following) is around two inches long (the male is around 4.5), and does not appear to have grown much, if at all. She has similar coloration to the male, save her tail has a white edging to it.

Now I've seen the female, usually she is very very reclusive, and hides in some driftwood. The male, on the other hand, is usually in plain sight, also on driftwood.

Today I noticed that my female's tail has split. It appears to be missing severals "rays" (not certain about the accuracy of the term), and I'm wondering if the male might have something to do with this. Do BN plecos get aggressive with the opposite gender? With different species?

Think it would be best if I removed the female?

IMHO i would say that the tank is approaching its bioload. at min u have like 23" worth of fish in a 20 gal and second being planted and having driftwood this tank may be overcrowded (ie physical space.) to my knowledge BN's don't get aggressive, i have 2 in a commune tank (30 gal) planted w/ some drifwood and they never have fin probs. Check all tank parameters ie chem stuff and try to suttly observe their behavior. these would be my first suggestions, always remember that even though the chem checks out ok, the fish could be stressed because they dont have enpugh "established terrotory" or favorite spots in the tank. as a discalaimer i have little to no experience w/ rasboras and their environmental requirements (space, zone, chem, behavioral traits)
Mabey the best first step would be to relieve the over all bioload, if your tank space and setup(s) permit.

Good Luck!

oops! thought of one other possiblity: they could both be males. i have had a pair of male common plecos that used to fight, most pleco species (correct me if i am wrong) males will butt heads, in general or in a confined space with once again a lack of establishable territory.