Im sure you pleco will be fine.
I have a little cory catfish that had his entire mouth bitten off by my since brought back to the store blue lobster!
ANyway, that happened a month or two ago and the little guy is doing great!
His mouth is even growing back! I noticed yesterday that his little "whiskers" are startin to grow back too! B) So anyway, my point is that your fish should be fine.
U should keep an eye on him just in case, but otherwise, enjoy your handi-capped pleco!
Is it just me, or do the injured/recovering fish seem to have the most character and tend to be favorites more often than not?!
I can't beleive I didn't notice this sooner, I got this small pleco and it looked in great shape the only problem is its missing a right rear fin, will it grow back or will he be without one fin? 
I feel bad for the fellow because it must of hurt, I know it wasn't one of my fish because I just bought him. 
Will it grow back or not?
