Larvae temps..what's too cold?

i wonder if some of my bad luck with larvae has to do with being too cold, same with new morphs...stream breeding sals larvae should be able to deal ok with 50 F (and mine in the past have) or so but as for vernal pool breeders and pond breeders this doesnt seem to be the case, i have not tried a side by side comparison of larvae with one exposed to cooler temps than the other, but it does seem i dont do as well with those kept in the 50-60 range, i had some recently at home that were 75 and i thought this was too risky so i transfered them to the facility where they were exposed to winter temps (50-60), and they didnt do well......esp with morphs my logic is that eggs are laid in spring and the animals will morph in late summer/early fall when the ground is still warm and they wont burrow down as far as adults so they must be better at warmer temps than adults? i just cant figure out why they would do poorly at temps adults can handle fine.

last year when i got that batch of axolotl eggs to try to raise-i left them to raise up in a fishtank in the biology lab, which is about 73 F and they didnt do well..infact they all died, even after i removed the survivors to a colder set up (50-60F).....so some of this might be species specific. i found that alpines did better in the parents tank-which is warmer than their baby tank since its up high on a rack....im wanting to know most from those who have raised lots of larvae, esp larvae of different kinds..could you provide a basic outline as in 'pond breeders do best at this...' or 'this genus does better at this...'

I tend to raise most larvae at around 65-70F, just because that's convenient for me.
IMO, water quality is much more important than temperature, as is food.
Got any test kits? Ammonia? Nitrate?

originally water was a problem after i moved to this new place because although it was well water...its from a spring (manitou springs) and must have something in it, i now use filtered water and have had no related issues since i changed over. i do have test kits but since im using filtered water i didnt think it necessary, i have also been told that the commercially available test kits are not very reliable in the ammonia and nitrate readings...my normal procedure is to do a 50-90% water change every couple of days, this did well for my annulatum (a fall breeder-btw), and my caudopunctatus larvae are doing fine too, my p waltls are also ok-but those are extremely hearty so that may not say much.....cynops arent doing so well, and some of my tylos are looking as if eggs might be in their future so i want to get some idea now...soon it will be warm here so i will convert over to a/c cooling which will make the room in the 60-70 range

I've raised C.orientalis at ~70F, no problems.
Decent test kits give a reasonable measure of ammonia, enough to indicate if something is wrong.
To be honest, after 40 years in the water keeping hobby, I don't use test kits any more, preferring to rely on my nose to tell me about water quality.

Oh yes, I raised axolotls at around 73F , no problems.
I really don't think it's temperatures that are the problem.
Take a good sniff over the water each day!

With A opacum and A maculatum, I have raised both at 65 F with no problems. I have also reared C. cyanureus, P. waltl as well as some of subspecies of Notopthalmus viridescens complex at the 65 F. I am currently rearing some C. pyrrogaster at a temp of 63-65 F and I am happy with the growth rate so far.

Ed

this is a really weird thought but i wonder if being 1 mile above sea level has any effect? we are known for having very high rates of 'blue' babies in humans ......

I'm currently having bad luck raising C. ensicauda eggs, and I'm wondering some of the same things. Since bringing them from the basement (62F) to upstairs (68-70F), they seem to be doing better (no more hatchlings have dropped dead). But I'm also concerned that this species may not like hard water (although the adults seem fine with it).

I hadn't even thought about altitude before; I'm even higher up than Paris. But it seems like pond species should able to tolerate a bit of low oxygen level, so I doubt it would affect them.

just out of curiousity, are you guys referring to the air temperature of the room where you keep your animals or the water temperature in their tanks? and how different are the two temps for you (my water tends to be a bit cooler than the air)?

i've got some T. granulosa that are just starting to hatch, so this would be good info for me, too!

I refer to water temperature, which for me is usually a few degrees F lower than the air. I suspect that cool temps (the coolest you can achieve indoors) are probably just fine for T. granulosa.