The latest revision looks good. I'm ready to call it finished and move it to Homebrews if you all agree.
Hold on, why on earth did I give it Hide +15? Must be a carry over from a previous beastie. It doesn't have any ranks or bonuses in Hide, so I should have left that skill out.
What about giving it some benefit from its "silvery scales" - maybe they help it hide in water? They're also supposedly easy to see when on land. Maybe add something like this:
Silvery Scales (Ex): When in clear, brightly lit water the reflections off its silvery scales give a cobra fish a +4 circumstance bonus on Hide checks. Contrariwise, a cobra fish has a -4 circumstance penalty on Hide checks if it is adjacent to a dark or non-shiny background (i.e. when crawling across dry land).
Thinking it over, I'm tempted to give it some or all of a snakes' racial bonuses to skills. Maybe at reduced numbers?
SRD said:
Snakes have a +4 racial bonus on Hide, Listen, and Spot checks and a +8 racial bonus on Balance and Climb checks. A snake can always choose to take 10 on a Climb check, even if rushed or threatened. Snakes use either their Strength modifier or Dexterity modifier for Climb checks, whichever is higher. A snake has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.
How's this?
Cobra fish have a +4 racial bonus on Balance and Climb checks. Cobra fish use either their Strength modifier or Dexterity modifier for Climb checks, whichever is higher. A cobra fish has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.
That works out to:
Skills: Balance +6, Climb +6, Hide +10*, Listen +5, Spot +5, Swim +10