It's always interesting how the mileage varies depending on the pond and the observer.

4CP, I suspect there is a reason why the BG prefer the worms and I if I had to guess it would be that the dried mealworms are very good food. I know you will appreciate what follows ... so I will share. An online source states that dry mealworms contain 53% protein and 28% lipid. So just consider them a 53/28 fish feed without added vitamins. Using average values for these two I estimate an energy density of 21,309 J/gram. So this is very comparable to dry GAM. The higher lipid content gives the Mealworms a slight edge on energy density. Please also note arbitrary formulations of feeds at Protein/Lipid contents of 48/18 and 40/12 respectively. For the these formulations I give no credit for plant protein ... basically using the assumption that LMB (and also BG) get no benefit from them. This is probably true .... otherwise ... it would make no sense to pay the extra for animal protein and one would see 80% of the conversion of a high quality 40/12 feed when feeding a low quality 32% feed that has a lot of plant based protein (something that doesn't happen so I stand by my assumption of the worthlessness of plant based ingredients for conversion in BG and LMB).

Using the 40/12 energy density, assuming similar digestibility of lipids and the animal protein components relative to dried GAM (something I have detailed energetics information for) I can make an estimate of digestible energy in an arbitrary 40/12 feed. It turns out to be less than half of the Mealworms. I noticed where one could buy bulk Mealworms for around $6 a pound. On a digestible energy basis, this would be like paying $2.40 for a high quality 40/12 feed. The 40/12 is a better value than the Mealworms in terms of $/digestible energy (based on fish meal and fish oil as protein and lipid sources of digestible energy). But given you love your BG and the BG love the Mealworms, I will not discourage it at all, LOL. Power to you and your pampered BG.

[Linked Image from i.imgur.com]

So I thought you might enjoy an estimate of conversion. For daily consumption of 1% of body weight each day at 75F, I estimate that dried mealworms convert at 0.67, that is, at 1 lb wet gain for each 0.67 pounds fed. Contrast that with 3% of body weight consumption of 40/12 which comes in at 1.46 FCR. (EDIT: Earlier posted an early version of the spreadsheet where 40% was tentatively used for the protein content of Soymeal and this should have been 48%. Making adjustments for that the FCR went from 1.25 to 1.46 at 3% of body weight and 75F.)

Snipe what say you? When you got the FCR result for the ~40% feeds at FCR 1.42 to 1.52, what was the rate of feeding? Was it 3% of body weight or was it higher than that?

The estimate for Mealworms is just what I said ... an estimate ... that relies on a similar energy profile of its lipids and proteins and similar digestibility of its lipids and proteins in relation to that of Gambusia. There probably are differences and the estimate is probably ROSY. But what I can tell you is this. It needn't be a mystery if you are of a mind to cage a few and find out smile.