Belly Full of Sand

Hello, all. I have a very young, 5 to 6 cm Axolotl I just got a few weeks ago and so far he has been doing well. His tank is set up with white aquarium sand. I have been feeding him bloodworms once or twice a day, and have noticed that he periodically passes a bit of sand (he does seem to ingest a few grains during feedings every so often). In any case, today I fed him like normal and when I returned to check on him I noticed (as he is still fairly clearbodied) that he has a belly quite full of sand. He is noticeably sluggish as a result, and is waddling around the bottom of the tank, rather than swimming about or floating in his plants like normal. Is this something I should be concerned about? Should I consider changing to large rocks on the bottom rather than sand? Any advice would be much appreciated.

For a baby of this size get I wouldnt have any substrate on the bottom just leave it bare, it wont hurt him and it will be easier to clean and monitor him.

I have removed the sand from his tank and he has passed all that he ate without any apparent difficulty and seems happy and spry once more, thank you for the advice!

You are very welcome, I hope he thrives for you .