Lethargic Adult Male - any advice?

Hi everyone.

About 6 weeks ago I purchased two leucistic, adult axies, a breeding pair of male and female.
The person I bought them from had been keeping African clawed frogs in the same tank (?!), and both axies had some gill/toe damage as a result.
The male had significantly more gill damage than the female though.

Right from the start, the female has been healthy and active. Her gills have grown in to a beautiful frill, and she eats like a pig.

The male has always been less active. At first I assumed it was because his gills were so damaged that he had limited oxygen exchange, but as his gills have (slowly) started to grow back, he has not improved.

If anything he is more lethargic.

At first he had a good appetite, but a few weeks ago he went off his worms (red wigglers). I had read somewhere that they could eat small amount of lean chicken, so I shaved a piece off a frozen chicken breast, thawed it in warm water, and fed it to him with tweezers, and he gobbled that up. He also is happy to eat bloodworms. There are a few rosy reds in the tank, and one disappears overnight every couple days, but I think the active female is eating them.

This morning when I went to turn on the light in their tank, I noticed he was in almost exactly the same spot as he had been last night, and his gills were looking very pale. I poked him with the turkey baster I use to feed him bloodworms and he didn't react. I thought he had died!
However, when I went to bring him to the surface for closer examination (I have a pair of soft silicone kitchen tongs that I sometimes use for feeding, and I was going to gently scoop him up with those), he did move a leg, so I left him alone.

I immediately did a partial (10%?) water change, and added a bubbler and airstone to the tank. I also floated a plastic baggie with a few ice cubes in the tank to cool it down, but I'm not sure they made a difference in the tank as it is large.

After a few minutes, I noticed he had moved on his own, and seemed to be interested in what I was doing, so I thawed some bloodworms and offered them to him. He ate a few mouthfuls from the turkey baster. Since then he seems to have perked up a bit, swam around a bit, and his gills have more colour.

I was reading a couple other forums where people describe their axies 'playing dead' and then being fine, so that was reassuring, but in light of his general pickiness with food and low energy, I am still concerned.

Some basic info:
The two axies are about 2 years old. I have them in a 50 gallon tank with a regular aquaclear filter. They were purchased with the tank and filter, so the bacteria were already established. There is a light and a few java ferns in the tank, as well as some artificial plants and a hide. Substrate is part sand, park river rocks, and part bare. There are a few small gravel bits mixed into the sand from the previous setup of the person I bought them from, but they are quite small (< 5mm), and I have seen the female pick one up and easily spit it out right away.
Temperature is room temperature - between 17 C and 20C depending on whether the heat is on. Tank gets only diffuse sunlight.

I don't have a water test kit (may go get one today), but the other axolotl and the rosy reds are fine.

Any ideas as to what the 'playing dead' episode may have been, and what to do about a picky eater who is also lethargic?
Aside from the damaged gills, he has no other visible symptoms, and so far seems to be at a good weight.

I forgot to mention - I do small water changes every couple days, removing a few liters while vacuuming out poop/ uneaten food, and replacing it with water that has been treated with a dechlorinator and/or sat out for 24 hrs.

The tap water here is slightly on the hard side.

I have previous kept aquarium fish with the same tap water, either treated or just left out overnight, with no problems.

Hopefully the image I attached opens correctly. The male in question is on the left, with his head towards the corner. You can see the colour difference in his gills vs the female on the right, and how much smaller they are.

Regarding hides, I have one 'hollow log' type ornament, and several plants. Before I got the log, they seemed pretty happy just hiding in/under the plants, but I may pick up another hide when I go to the pet store to see about a water kit.

I will try blanching the worms. I have tried cutting them up and mixing them in with the bloodworms, but he just selectively spits out the bits he doesn't like.

The tank temp is perhaps too high - it looks like it's reading about 21. I guess the light may be warming it warmer than the room?

Also, Layna, your profile pic is too cute! What an adorable pose

As suggested I purchased another hide and some water test strips.
Everything was normal except that nitrites and nitrates were right on the high end of 'normal'.

I have done another partial water change and advised my family to keep the thermostat down so it doesn't go up over 21.

I think I will increase the volume/frequency of water changes, perhaps do one every day for a few days to get the nitrites/trates down, and try my male on blanched worms then.

Axxies tend to LOVE worms, and they're packed full of nutrients. I find them the best food for both sick and healthy axxies.

Now, to your male. I agree with Layna. Older axolotls tend to be more chilled. I also find my female is more active than my male, but whether this is because she might be slightly younger or because she is a different type, I don't know. Your male looks a good weight and generally healthy - axolotls who are still, or inactive, often go 'pale' - their entire bodies are paler, and their gills are a very dull shade of pink. This is completely normal. The blood rushing to the capillaries in the gills is what causes them to go pink/red and is much more noticeable in the lighter varieties than in the darker colours.

A few pointers, though, if I may. I would recommend getting a liquid test kit if you can, rather than the strips, as the strips appear to be less accurate than liquid test kits. I personally use API Master Freshwater Test Kit. It costs £20 from Amazon, is easy to use and lasts ages. It has never given me reason to doubt it.
I would also remove the pieces of gravel if you can. I would be really worried about them swallowing them, which can result in damage to their intestinal tracts, impaction and death - the fact they're small is even more worrying, especially if they are fed from the bottom. Sand is fine if they have a feeding bowl or if they are fed from above, for example, with tweezers or a turkey baster.

Be warned that axolotls LOVE to play dead. Gally, my Golden, often does what I call 'sleeping' - she will lie stock still, gills still, no movement, not responding to voice or movement. But she is fine - she is just resting.

Also, I love your female's trident gill! So cute.

Thank you so much Petersgirl, that was very helpful. The blood rushing into the capillaries when they move around makes sense.
I panicked because I used to work at a vet, and the colour of his gills was the sort of pale I have only seen before on severely anemic dogs and a cat that bled to death after popping some internal stitches, so I was conjuring all sorts of scenarios where something was terribly wrong with him.

I do plan to get a liquid test kit eventually, used to have one when I was into keeping fish but got rid of it years ago (if only I'd known!). The ones at my local pet store were quite a bit more expensive than the strips, and I didn't want my partner to freak out about how much money I spend on the axolotls :happy:.
I also didn't think that water would be really out of whack, so just wanted a basic check that nothing was off the charts, but you're right, the liquid kits are much more accurate.

Anyway, since the addition of a bubbler and extra hide they are both more active, so I guess that's what they wanted.

You're right - Sally (the female) has the cutest little bifurcated gill:happy:, it's how I told them apart when I first got them.

I like my axxies to have one hide each so they have somewhere to go for a bit of space, but I actually have 5 at the moment for my two They love them. I also like to have a bubbler since they play with it, it stops my water from stagnating and introduces more oxygen into the water.

Don't worry - lots of normal axolotl-based things are pretty startling at first and you definitely wouldn't be the only one who's ever freaked out over it. Yawns, cloacas, pale/red gills, colour-changing skin and feet, that weird gap behind their gills that means food sometimes falls out...you name it, it's caused a bit of a shock the first time!

Oh, and the money...yeaahh. Axxies can cost a bit once the bug hits you. Case in point: an axolotl costs around £19 at my LFS. My tank cost £70 preowned, my filters came to £45, my hides cost me about £45, my filter sponges have probably cost me about £24 so far, Stress Coat about £24 so far, Polyfilter about £45 so far, test kits £40 so far, worms around £40 so far...
And that's without electric and water costs. But they're so worth it! My partner loves our babies but I had my heart stolen by a grey WT female, and he had to remind me how much it would all cost again to keep her since my tank is only 26 Gallons, and my babies are getting bigger. He helps reel me in when I sometimes get blinded to how much work another will be.