[Peter Finke]

A remarkable and helpful comparison, but a disturbing and question-rising, too! First,many thanks, Martin!
Then: The influence by different food is highly probable, since it is well-proved in all of these cases. But could you exclude other accompagnying factors that may trigger those colour differences additionally? If not, it is surely remarkable in its own that food is suffcient for making that difference.
But other questions arise concerning structural features. The caudal of the first (red) fish seems to be slightly more elongated; in its son (or grandson) in picture two it is much less developed. Or is this an illusion that is caused by different perspectives of the photos? (I think a bit on the case of the difference between tweediei from Western Malaysia and the certainly closely related phoenicurus from Sumatra. It was stunning that the elongated shape of the wild caught spec. Langgam was nearly lost in the generations bred at that time mainly by Martin Fischer. At the same time the limited red zones of the father fish in later generations extended over large areas of the unpaired fins of the sons and grandsons. But that’s colour; your series shows how uncertain it is to rely for species determinazation on that!).
Certainly not caused by food (or would you say even that? I don’t think so) is the remarkable difference in the length of the ventrals with respect to the Mimbon-fish (the last picture). I have not seen such a big difference within one and the same Paro-species (with the exclusion of so-called “blue line”; that is no scientifically controlled species however; it’s a trade name only used for surely different fish from Sumatra. I had some with very long ventrals indeed and at another time some with very short. Nobody was able to control their identities. Probably that were different fish bearing the same trade-name.) Here, you place the Mimbon98 within the range of alfredi (as I know well; you gave me one of the last young males). Are there other examples for a Parosphromenus-species with such a variability of ventral-length? If any one could say, it’s you. I never have encountered that (well: perhaps with some “bintan”, but that’s the same thing as the blue-line problem: mostly trade fish without approved identity).
To my opinion, I should place the first three and the Mimbon not wthin the alfredi range. When I remember correctly, Kottelat and Ng in their description did not mention such a big difference in verntral length as pypical for alfredi. But as I said: Especially wth this species you are most experienced. Here, I believe what you believe.