Salamander larvae suddenly dying

[EllieWind]

Hi, everyone, it's me again.

I collected some tiger salamander eggs from near my cabin a couple of weeks ago and have been raising the larvae with no problems for a week. Just last night and this morning I had 2 of the 31 larvae die. Both of them were lethargic and refused to eat any brine shrimp before they died, and both ended up with angled/curled tails. Today I have 5 more displaying the "symptoms" and I'm worried that whatever the issue is will cause me to lose the entire brood. I should also mention that I had my brine shrimp hatchery stall a few days ago (probably due to a cold front that came through) and was unable to feed my babies until I could get the shrimp hatching again at a normal rate. I had moved the babies into the fridge during the two days it took for me to start another batch of eggs and I'm concerned that the lack of food and sudden slowing of their metabolisms may have also contributed to why they're doing poorly.

I've separated the 5 from the rest and have added some Indian almond leaf to both of the tubs, but is there anything else I can do?

 

[EllieWind]

Two more just died. One didn't even show any signs. Anyone have any idea why they're dying out of the blue?

 

[Herpin Man]

Are you doing regular water changes? Are you rinsing the brine shrimp before feeding? Have you tried daphnia or minced blackworms? Are you keeping them cool? What are you using for filtration?
There are quite a few variables that can affect mortality, I have found. Sometimes, the weaker individuals die regardless.

 

[John]

What temps and what water are you using?

 

[EllieWind]

I do at least 2 100% water changes daily and use dechlorinated tap water. Yes, I rinse my brine shrimp before feeding. I haven't been able to get a supply of daphnia or blackworms (either sold out online or unavailable), so I've had to rely solely on the brine shrimp. It's been warming up here and their water has been pretty consistently at 68° and I have been using fans to get the temperature down to 65°, but that's been a bit of a struggle. I keep them in shoe box sized plastic tubs so I don't have any filtration going on. I raised axolotls this same way and lost about 10 within the first 2 weeks, but never this many and so suddenly (I just lost 12 more overnight).

 

[EllieWind]

The temps have been a little frustrating since it's warming up and my apartment doesn't have AC, but their water has been staying around 68° and I have fan over them now to try and get it down to 65°. I use dechlorinated tap water, which so far has never been a problem for my other amphibians.

 

[EllieWind]

Just lost 12 overnight and all but maybe 1 look like they'll be on their way out soon judging by their angled tails. I'm gearing myself up to lose all of them and will try my hand at raising tiger salamanders from egg next year.