I have been keeping a grown female bristlenose in a 19 gallon tank together with 3 peppered corys, 3 one-two inch juvie bristlies, a platy and 4 amano shrimps for the last couple of weeks. tbh this was not the arrangement I would have chosen, but it was either that or let the world be flooded with little baby bristlies. Anyway, what I have found was, there was a tiny ammonia spike when I first added her, but that was easily sorted with a few extra water changes. There is more dirt on the bottom and I am doing two weekly gravel vacs instead of the one, but it's not unsurmountable. I am extra concerned about keeping the tank clean because of the corys and their sensitive barbels, but we've been fine so far. I am a little worried about what I'll do when we go away for 2 weeks at Easter, I'll certainly try to sell the juvies before then, and maybe put her back in the big tank with a tank divider- or even let her have one more batch of fry in the big tank (yes, Mr Bristlie, you do get to have sex, but only 3 times a year, when we go on holiday). But when I'm here and keeping an eye, it seems to work ok.