So I picked up five bristlenose plecostomus (plecostomii?) that are about 1.5 inches long give or take from a local person, and I put them in a 20 gallon tank that has been running for over two years without anything but the water and a plant.

The tank itself is filtered with a reverse flow undergravel system with about 2.5 inches of substrate (round 1/2 inch gravel topped with eco-complete and then a cap of regular aquarium gravel). I use two Power heads to pull water through two 40 gallon rated sponge filters and the output from the power heads (using a venture tube to pull air from outside the tank) blows the water and air down the riser tubes.

As the tank hadn't been cleaned or scraped there was a bunch of algae, and these plecos are really cleaning the tank up. I have once a week been pulling 25% of the water or more with a 3/8 inch syphon (rigid line 3/8th into flexible hose at 3/8) that will suck up aquarium gravel.

My plan for this tank is to replace the power heads with better quality ones (using Penguin 660 power heads now), change the twin T5 tube fixture to an LED fixture, pug in some plants, and then stock the tank.

My wife wants guppies (ick) but as the tank is in our bedroom it will probably get guppies (purchased from a local breeder so they won't be the sick, puny, fragile guppies at most pet stores).

Once the plecos get this tank done I will put them in another 20 that has a colony of panda corys (the tank in my son's room). And when the plecos are big enough to not get eaten by a 12 inch long Raphael Striped Catfish they will go in the main tank (75 gallon) to get rid of some algae there