Cyberglass' Aquana: I see you've used purple for the outlines except for the darker blue colour. Imo it looks good, but something doesn't seem to fit. It's a simple sprite, but there was too much usage of shaded outlines, making the default black lines stand out in a bad way.
tnguye3's rock fakemon: I see, a fusion it is. It looks pretty rocky, good job on that one, but it's right arm seems to have a diffrent lighting than the rest of the body.
icychill66's ice tiger: Looiks like the base you've used is growlithe. Growlithe's perfect for making tigers, Theres nothing really wrong with it when it depends on editing the sprite. but the highlight on the head seems a bit too light imo.
Ark_Silvanos' fire tiger.
Fire's a pretty hard one to pixel. You did a good job on the fire. The body is pretty much sudewase and there seems to be no shading of the tail on the leg of the fire tiger, while you lighted it's belly because of the fire next to it. Mind that fire always wants to go upwards, not downwards.
Now it's time to decide which one I'm going to choose of these. I choose
Cyberglass. The fire tiger is second.