really mean pocastamus

Question
We have a 5 gal tank for our daughter. We started out with 2 fancy guppies, 2 neon tetras and a yellow pocastamus. The pocastamus died and so we got a new one, brown this time. One by one the fish started dying and were no where to be found either. We are now left with the pocastamus.  We went and bought a fancy tail gold fish.  The pocastamus chased that poor goldfish around and only hours later we noticed scales missing. Now, less than a day later, the gold fish died as well.  my questions: Are all pocastamus' this mean? We put him in there as an "algae eater"...now what? can we keep other fish in there with him? What kind or size do you recommend for a 5 gal. tank? Thanks!

Answer
Well a pleco fr a 5 gallon tank would be a clown pleco they get a max. size of only 4 iches. When you buy fish try to introduce the fish at the same time so they won't become territorial against each other. The tank is to small to have a pleco and the other fish i would reccomend a ten-gallon then you could have some fish with the pleco.