jpsdad, this pond absolutely had/has some kind of nutrient load that, earlier in the spring/summer manifested itself as a green film covering much of the water surface. However, that all went away from mid-summer into the fall.
Interesting thought about fatheads supporting maintenance or growth. In the case of this pond, the stocking of all species of fish (SMB, YP, BG, CC, HSB) were of all different sizes at the times of stocking. So, I can't really get growth info. as we did not tag or fin-clip any fish. My comment about not seeing the growth is more anecdotal in that the fish don't seem overly plump like we see in other ponds.
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I know that none of these answers are definitive.
OK.
I would think that the fatheads supported both maintenance and growth at least during the period(s) when the standing weight of consumers were consuming above their maintenance requirement. The maintenance requirement is what limits growth and when the pond plus feeding provides exactly what the standing weight needs for metabolism the fish will stop growing and limit will have been reached. Mortality, eg harvest and/or natural mortality, will reduce the standing weight and thus allow individuals to continue growing. If a fish doesn't consume its needs for metabolism it will resort to mobilizing its own nutrients (IOWs it will eat itself and lose weight). Such a condition where consumption is insufficient for metabolism leads to weight decline would definitely cause low relative weight where it occurs over extended periods. On the other hand, when a fish consumes above its needs for metabolism it will grow and has the opportunity exceed standard weights if it is gaining rapidly enough. So the difference between Lee's fish and the plumper fish you noted must be sourced solely with how much energy they are eating individually.
That's why I was asking whether the source of low clarity was phytoplankton (green water) or turbidity. Individually the fish need to eat more. Perhaps Lee could feed them more if the nutrients aren't already excessive. Or do a combination of additional feeding and harvest to ensure individual fish are getting enough food to continue growing. If the clarity issue is green water then I don't think I would increase the feed rate for sure. Feeding by hand, I don't imagine he is feeding an excessive amount of feed which troubles me given earlier comments. If the feed is moderate and the low clarity caused by intense bloom then there must be a lot nutrients flowing into the pond or possibly in the native soil.
