hi Matt
whereabouts r u? If in Oz, could be heat related or water quality? What is temp of your tank and water parameters - ammonia, nitrites, nitrates, ph levels. Sorry to hear about Pip. How is Axy? I know how distressing it is when you lose a pet and another gets sick.
* If you haven't already done so, as Coffo says you can put him in the fridge (as long as your fridge temp is not lower than 5degrees celcius = if unsure check by placing a thermometer in a glass of water in the fridge and check after 5/10mins)
* Then if ok, place Axy in a foodsafe container with fresh dechlorinated water.
* AS he is lopsided; just put enuf water in to cover his top fin but allow his feet to rest on bottom of container.
* Keep a bottle of dechlorinated water in the fridge beside the container as you will be doing FULL daily water changes.
* Offer food at water changes but he may not take food as his metabolism slows down in the fridge (at cooler temps).
* Wrap the container with a towel to stop the temperature spikes (when the fridge door opens/closes and also cut down the glare from the fridge light)
Keep us posted and if any questions please feel free to ask, I may not be able to help on a lot of things, just what I have picked up from being on here, but there will always be someone who can help or point you in the direction
.
* Also, if you don't have a water testing kit, get a sample of your tank water tested at your local petshop/aquarium.