...Ive had this specimen in particular for 2yrs and also 3 other reg. Wels for around a year before they canabolised or succumb to extreme ich from cold temps. All 4 of them broke out with ich every time the temps dropped below 70-72 degrees.
***Right, I remember that now. You described it somewhere here.
My current albino shuts down feeding in cooler temps and shows ich spots almost immediatly. Soon as the temps raise back above 76 the ich goes away and he begins begging for food 24/7 as i deem "normal".
***Right, I remember that now too. Sorry.
My theories for this could be location there coming in from.
***These observations are very hard to rationalize for me too. It's easy to criticize yours but I have nothing much sensible else atm to offer as an alternative. The only thought I am having is that perhaps, it is not wels you got but a very close (sub?)tropical relative and a look-alike. I know, I know. I'd not dare to challenge Wesley Wong aka Fugupuff and you, Wednesday on the ID. I just don't know how else to explain what you observe.
If their farmed in spain or somewhere warm as opposed to coming in from europe where they actually are a cold water native species.
***Spain lies, needless to say, in Europe. The wels range of temps is ~ as wide as it gets. Sure temps above 80-85 F (e.g., summer in lower Volga, southern Russia, Kazakhstan, etc.) are hard on them in the wild, I'd think, and the wels seek out deep cool pools... but as far as the low range - no problem even being for 7 months under ice in Siberia. It's in their DNA, I'd think, no matter where they have been raised. Anyone knows different???
Most of the larger ones these days are caught in the rio ebro and the european ones seem to be smaller.
***I didn't know there was a distinction between those in Ebro and those throughout the rest of Eurasia. Can you elaborate please where this is coming from? BTW, I've read in Ebro the Spaniards feed their wels by ~ truckloads of food... to grow their fishing tourism.