After these guys hit a foot how fast should they grow? I have had mine for a year and half now. For about the first year he was growing around an inch per month. Once he hit about a foot his growth has slowed down tremendously. Is this normal? He is housed alone in a 120g no ammonia, nitrate below 12.5 mg/l, nitrite ~.3 mg/L pH = 7.0; mixed diet of shrimp, crays, smelt, muscles, krill, vit supplement. Thanks