Very good, let’ s see what comes out. Certainly, those temperature measurements of the fish catchers were all taken in daylight.
We must bear in mind, however, that Parosphromenus live in streaming waters, not in stagnant waters. That means probably a little more stability as temperature is regarded, but there should be a certain fluctuation nevertheless.
Of course, it will not be easy to interpret the results of your experiments since you probably cannot guarantee laboratory conditions. But let us see. At any rate, it’s the first time that somebody of this network takes personal measures in order to prove a hypothesis. That’s fine, indeed!