Question: Unexplained deaths of young Axolotls

I am new to the forum and hoping someone can help me out with suggestions and / or information.

I have a number of young axolotls born about 3 months ago. They have been growing well and look like miniature versions of their parents. Recently however a number of them have unexpectedly died for no apparent reason.

There were about 30 - 35, housed in a 30 gal aquarium in about 8 " of water. Ammonia and nitrite levels are at or close to zero. Water temp is 58 F. The water is filtered by a sponge filter that provides very mild areation and water movement. They are being fed exclusively on freshly hatched brine shrimp well rinsed before feeding. Regular weekly water changes of about 10% are being done.

Approximately one week ago I found one dead in the tank and removed it. The next day 4 or 5 more were dead. A day later same thing. A couple of days passed and then another 5 were dead. I've checked the water parameters again and done about a 30% water change using about a 50/50 mix of aged water (from the adult axolotl tank and fresh dechlorinated water) yet the deaths keep coming. I'm down to about 15 survivors now and don't want to loose any more. They are all eating well and it is fun to watch as they lunge at the brine shrimp when added to their tank.

No more deaths today I am pleased to say but very worried more may occur at any time.

Any help, suggestions or explanation as to what I should do or not do would be very much appreciated. I have about sixty 3 week old axolotls growing in another tank and they seem to be doing well but I don't want the same thing to happen to them as they grow older.

In addition to the young noted above I have 5 adults, one GFP male, one albino female, one lecuistic female and one lecutistic male and one male melanoid. I've had them for just over a year now and they have tripled their size since I first got them and they continue to do well. All are about 7- 8" in length

Thanks in advance for your help.

What was the nitrate levels? that many axolotls would be producing a good amount of nitrate and that might have built up faster than you thought.

How big are your babies? It's possible they're just monsters, but mine are over 2" at 7 weeks old, and are way too big for baby brine shrimp. Are you sure they are getting enough to eat? It seems like by 3 months they should be able to take something quite a bit more substantial than baby brine shrimp. I would suggest separating them to prevent any further transmission if it is some kind of bacterial or viral disease, and transitioning them on to chopped or whole blackworms or bloodworms if they are big enough to take them. Good luck!

Thank you for your interest in my predicament.

I tested the nitrate and the reading is 0. Ammonia and nitrite remain as previously noted. As for size the remaining ones average 2". Knock on wood, they are all doing fine at the moment and there has not been anymore deaths in the past few days. They seem to be doing quite well with the brine shrimp and readily fill their bellies each and every feeding. I can actually see full bright orange bellies on the GFP and lecuistic ones after feeding.

I have frozen bloodworms that I can thaw, chop and feed but have heard that they can often be hesitant to accept dead food after chasing live food like brine shrimp. I can certainly try and maybe make it a little more appetizing by feeding some small pieces along with the brine shrimp. I'll give that a try and see what happens.

I'm not sure what went wrong initially but am hoping the daily losses are over. I am of course always open to suggestions form those of you with more experience. I'll try to get a couple of clear photos and post them soon.

At about three months old, they should be on larger food such as blood worm/ blackworm/ chopped worm.

Axolotls - Feeding

Just a quick update. One more has passed away but the rest seem to be doing well.

I have started feeding chopped up blood worms and they accepted them without problem. I'm still feeding some brine shrimp as well to keep them interested but believe a few more days and I'll switch to blood worms only.

Still no apparent cause for the sudden mortality which prompted my original post so it may remain a mystery. Fingers crossed that is in the past and the remainder will thrive.

Thanks to those who offered up an opinion. Very much appreciated.

I'm wondering if the tank is cycled - you say both nitrites and nitrates are at or nearly zero. Could that be your problem?

Tank was cycled for more than a month before the problems began. Mature (6 month) sponge filter running in tank. Remaining ones are doing well now and have readily accepted the blood worms which I am feeding twice a day - before and after work. No more losses recently. Hopefully that's all over for the foreseeable future.

Regardless of how long the tank was cycled, if both the nitrites and the nitrates are at zero, the tank has crashed and needs to be cycled again.

Is it the first time you used the tank? Chemicals on the glass, or brine shrimp equipment?

So glad everyone is doing well! Mine had no problem switching to bloodworms either. It seems from the pattern of deaths that it was most likely some sort of contagious bacterial or viral disease. I would disinfect any equipment that is used in multiple tanks, and you should be all set.
Sweetie: both ammonia and nitrite readings should be at zero in a cycled tank. Nitrite at zero is a good thing, as nitrite is poisonous. Nitrate levels can be pretty low with frequent large water changes, small amounts of waste for the size of the tank (low bio load), a tank with live plants, or a large surface area for gas exchange, as it will diffuse out of the tank and into the air. As long as ammonia and nitrite are reading zero, low nitrates aren't an issue. If your tank is cycled and you are getting readings of ammonia or nitrite, I would recommend adding additional filtration media, as it is a sign your filter is having trouble keeping up with the bio load in your tank.

rachel1 said:

Sweetie: both ammonia and nitrite readings should be at zero in a cycled tank. Nitrite at zero is a good thing, as nitrite is poisonous. Nitrate levels can be pretty low with frequent large water changes.

Click to expand...

I am aware the ammonia and nitrite readings should be zero. My concern was that she said the nitrites were at or near zero but that the nitrates were zero. The nitrates may well be low, but they should not be zero. If they are, it usually means the tank needs cycling again.

Thanks to everyone for all your responses and advice. Water quality levels are good and the axolotls are doing well. They are voracious little ones and attack the blood worms at every feeding. Hard to tell for sure but I believe they have grown a little since starting the blood worms.

I've increased the water volume slightly and am watching carefully. As they grow both water volume and filtration will be increased using both well cycled water and filtration from other healthy tanks. I'm expecting good things and will keep you advised.

Thanks again.