ichthyomorphic

from The Century Dictionary.

• In decorative art, noting motives based on the forms of fishes.
• In zoology, having the characters of a fish, or morphologically related to fishes; ichthyopsidan.
• In mythology, formed like a fish, altogether or in part; partaking of the form or character of a fish: as, the ichthyomorphic gods of ancient Assyria and Syria. See Dagon.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Fish-shaped.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Shaped like a fish.