I think fishes is a pretty cool guy.eh is well-supported archetype and doesnt afraid of anything

http://yugiohccg.wikia.com/wiki/Pelagic_Legion
This card shows the adaptability of Fishes. It can be summoned over other Synchros when you are being pressed or in need of relief and thanks to its lower level, it requires less resources. Run at two.

http://yugiohccg.wikia.com/wiki/Koi_Moroi
If you need that last piece of Synchro Material, Koi Moroi is an excellent and adaptable card to use. Run at two, perhaps.

http://yugiohccg.wikia.com/wiki/Splash_Woman
Simple swarming power for an instant Synchro (and Megaman-themed name, nice one). Don't run at more than two, it seems like it clogs.

http://yugiohccg.wikia.com/wiki/Hidden_Synchron
Outclassed by Back-up Guard, but a Fish tuner and an adaptable one at that. Side perhaps?

http://yugiohccg.wikia.com/wiki/Mystical_Coral
A fantastic tutor for Fish, offers them depth (pun) and hand replenishing power. It's a little slow, though, so run at one or two and side the others.

http://yugiohccg.wikia.com/wiki/Large_Mouth_Bass
It's level limits its potential a lot, making it essentially a slower Shura. But with this, you could pull out both Back-up Guards and another Level 2 Fish (of which there are a fair few), or just pull out a single Back-up Guard and another Level 3 to synch for Pelagic Legion. Run on preference, but I would go for one or two.

http://yugiohccg.wikia.com/wiki/Eldritchfish
A reasonably good boss card made a little faster with its handy Special Summon. You can pull it out after normal summoning Splash Woman or School Leader and use the generated fodder cards as tributes. It's destruction effect is nice too. Can be sided on preference, but running it at two would be a good option.

http://yugiohccg.wikia.com/wiki/Airbag_Pufferfish
An interesting hand trap that isn't particularly good, but fills the graveyard for cards like Black Charged Fish and can help out in a crisis. Provides much needed level 2 support. Can also be sided in other decks. Run at three.

http://yugiohccg.wikia.com/wiki/Rising_Tide
Lets you pull out an Eldritchfish from anywhere at any time, although it can clog depending on how many E-Fishes you run.

http://yugiohccg.wikia.com/wiki/Soul_of_the_Fish
An essential card. The emphasis on the hand in Fishes is often difficult to bear and you may often be in need of help. Run at three.