The dolphin (porpoise) statistics really didn't cut it. So I came up with these statistics instead. Any feedback would be appreciated. Thanks.
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FISH
Tiny Animal (Aquatic)
Hit Dice: 1/2 d8 (2 hp)
Initiative: +2
Speed: Swim 60 ft. (12 squares)
Armor Class: 14 (+2 size, +2 Dex), touch 14, flat-footed 10
Base Attack/Grapple: +0/–12
Attack: Bite +4 melee (1d3–4)
Full Attack: Bite +4 melee (1d3–4)
Space/Reach: 2-1/2/0 ft.
Special Attacks: —
Special Qualities: Blindsense, low-light vision
Saves: Fort +2, Ref +4, Will +1
Abilities: Str 3, Dex 15, Con 11, Int 1, Wis 12, Cha 2.
Skills: Listen +2, Spot +2, Swim +6
Feats: Weapon Finesse (bite)
Environment: Temperate aquatic
Organization: Solitary, pair, pack (3–10), or school (20–100)
Challenge Rating: 1/6
Advancement: 2–3 HD (Small)
Level Adjustment: —
The statistics here can describe any migratory or sedentary fresh or saltwater bony fish, such as a carp or a salmon.
Blindsense (Ex): A fish can locate creatures underwater within a 30-foot radius. This ability works only when the fish is underwater.
Skills: A 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.