I have a 55 set up right now..
The bristlenose only gets about 4 inches. Tops out at 5 inches, for the largest ones.. That is why I picked this type of algae eatter. And you can sex them by the bristles. Males have more and longer bristles. The females some times never get bristles..
I also have a 20 gallon regular, 25 long, I believe a 40. An antique 5gal that has the metal edges on the whole tank. And about ten 10 gallons. But these all are not set up. Well the 40 and 25 long are out back with water in them. I put big rocks in there to get algae on them, to feed my plecos..
Getting attached to fish. I believe it.. I had one fancy goldfish for 10 years.. Tank seems empty with out him. Some of my fish actually have names. LOL.. I guess they can be as addicting at chickens. I had fish before birds..