boldtogether;4138974; said:Wow. If you could build a tank to pump all the fishs' solid waste to, you WOULD have a small scale treatment plant. A digester would produce methane and you could burn that to heat a heat exchanger for tank heating...the sludge from the digester could be dewatered and composted, sold for big $$...perpetual. People on this site amaze me every day...I am humbled.