Gills turning blue, losing red color

I have three axolotls in a tank with two guppies and plenty of snails. The axolotls, which have been in the tank for about a week, looked pretty good up to today, when I noticed two of the axolotls' gills were turning blue and becoming pale red. The third one's gills look normal, and he swims around the tank much more than the others, which are pretty lethargic.

To my untrained eye, it looks like they're losing blood flow to the gills. Is this an infection of some kind, or something to do with the tank environment? I've done some Googling, but I didn't turn up anything on blue gills. Thanks for any advice!

Not the greatest picture, but you can sort of see the blue lines creeping up the gills.

http://homepage.mac.com/y2aak/.Pictures/sickaxolotl.jpeg

Hi Akanarek,

You are right that the gill colours change according to blood circulation and perfusion to the region. Increased blood circulation occurs during periods of physical activity such as during feeding and breeding. Some axies also develop more pigmentation around the gills as they mature. I am not particularly worried about the gills if there are no other signs of stress and illness.

Cyanosis (turning blue due to lack of oxygen), blood stasis (congestion) or polycythaemia (thick blood), commonly seen in other terrestrial animals do not occur as dramatically or as commonly in axolotls. Axolotls are able breathe through their gills, buccal pumping (gulping air) as well as to a certain extent through their skin and mucus membranes. Provided you maintain the water parameters well and do not expose them to toxins, there is very low chance of such occurences. Any congenital defects (such as heart or blood problems) will long manifest while the axie is still a juvenile and would present with other much more serious accompanying signs of illness.

The thing i am concerned about however, is the presence of gravel substrate in your tank. They appear small enough to be ingested and can potentially cause fatal impactions. I would recommend you to remove them. You can keep axies in a bare bottomed tank or with sand substrate.

Also it is advisable to keep axolotls with only axolotls of a similar size and not other tankmates. Feeder fish is fine with minimum 30 day quarantine beforehand. I personally do not like snails in the axie tank. Some snails are able to grow to a size that the axie can ingest and cause impaction. With snails, you either keep very tiny ones or extremely huge ones (bigger than axie's head). They also require quarantine beforehand to prevent spread of parasites and disease.

Cheers.