[Sneaky]

A red hi fin pleco is a very large pleco.
These fish grow way to big for most tanks.
Max size for this pleco is about 24 inches.
For a 15g tank, there are few kinds of small
plecos, however most of these do not eat algae,
or are poor algae eaters.
A Bristlenose Pleco is a good algae eater, but many
people do not like the way they look. Rubbernose Plecos
are also a good choice for a small tank.
For a 15g tank, the best choice would be either:
Bristlenose Pleco
Rubbernose Pleco
Ottos (4 would be a good number)
An Apple Snail
Some Algae Eating shrimps, like cherrys, amanos,
ghost shrimp, etc.

All plecos produce huge amounts of poop, so keep that in
mind when considering them. They require extra maintenance
on a tank because of the sheer amount of waste produced
by them. For a smaller tank, there are better options
than plecos.