Aggressive pleco?

[LizardQueen]

I got three a while back from petco- great place for fish amirite? Yea so They did fine for a while but the hypo colored one one day just flipped a switch and now is aggressive. :C so much so that i went a few days not knowing what was chewing my aro and then caught him in the act. Removed him to the time out tank but I have never seen this behavior. :L what do I do with an aggressive fish that tries to kill everything. Or why is it doing this when the other two are so peaceful.

 

[Warborg]

There are several reasons for an aggressive pleco.

1) Feeding issues- A hungry pleco can make a dangerous pleco. Be sure to be feeding the pleco(s). Don't expect them to just get leftovers. I have a pleco that gets nasty with it tankmates during feeding but gets along with them otherwise.

2) Not enough hiding places- They may attack others if they feel they can't hide.(I don't think this one is your problem).

3) Tanks too small- Title says it all.

4)A fish(es) already attacked the pleco first- The pleco will remember and consider that fish an enemy.

5) Habit- 1 through 4 may have already happened and the pleco just got used to it.