Currently 2 small delhezi bichirs in 40 breeder. 3ish inch and 4ish inch. Penguin 350 filter (up to 75 gallons). Looking to upgrade to maybe a 100 gallon when they get big. Until then, probably at maximum capacity. Does anyone know how much retropinnis bichirs cost when they are big? A small one is already $69.99 on liveaquaria.com which sounds crazy expensive to me.So what the next poly to get?