iv got a bit of a problem with my old platy, shes 2 years old, and she normaly comes to the glass to say hi and all ways the first to the food, but now she just at the bottom of the tank with no life in her at all, shes not pregnant and shes only eating very little, i put her in a sperate keep net in the tank for 4 days but she still the same, could this be just old age or is there a problem, all the levels in the water are fine as i took a sample to my local shop yesterday