Cards to add:

Big Wave Small Wave: Allows you to summon a WATER monster, then get rid of it to summon Coelacanth immediately.
Mausoleum of the Emperor: Summon Coelacanth for 2000 LP.
Gold Sarcophagus: Search for Coelacanth to get him as early as possible
Moray of Greed: Draw Engine to help return Coelacanth targets to your deck, while also giving you more chances to draw into Coelacanth.
Giant Trunade: helps you clear back row before OTK'ing.

The 1st thing you should understand is that for a Fish deck, the entire point is summoning Coelacanth and using his effect then synchro summoning some level 7/8 monsters so you can either OTK or deliver a huge amount of damage in a single turn. Therefore, you should focus your deck more on being able to find and summon Coelacanth. The deck just doesn't function well without him.

Cards you can say good bye to:

E Hero Ocean - he does nothing here...
Cranium Fish - just creates dead draws since as a 6-star monster even with Legendary Ocean he can't be summoned without a tribute. I suggest at least not using 3 copies. Keep it down to 1 or 2.
Ocean's Keeper - all the strategies surrounding him are too situational and don't do enough to actually hurt your opponent so he isn't worth playing.
Thousand-Eyes Jellyfish - same as above.
Water Art Aoi - use 1 at most. It's a somewhat situational card and it makes you lose field presence.

Additionally, if you're using both Mausoleum of the Emperor and A Legendary Ocean, I suggest adding 1-2 copies of Terraforming along with Earthbound Immortal Chacu Challhua (who is also a Fish), which provides you an alternative powerful monster other than Coelacanth that you can summon. You may also want to consider using a 3rd Pot of Avarice since you now will have more ways of getting Coelacanth out quickly and being able to re-use his effect is important. Just test it out and if you don't like it you can bring it back down to 2. Other cards you can test out include My Body as a Shield so that your Coelacanth or Earthbound Immortal doesn't get destroyed as easily, and Star Blast is another easy means of summoning Coelacanth. Water Hazard is potentially another card worth testing as you can set up plays with Royal Swamp Eel to get some quick high-level synchros out.

Edited

Thanks for the fix

Moray of Greed is not in KCVDS

You never stated that the deck was for KCVDS. Unless you state it, I make edits using all the cards in the game. KCVDS is missing 2 major packs and many random cards from older and current packs.

EDIT: Also, I never told you to make your deck have more than 40 cards. The deck absolutely needs to be at the 40 card minimum to give you the best chances of drawing Coelacanth as early as possible.

Edited

Which 4 cards should i get rid of.

Edit: You also did not told me not to make the deck more then 40

-1 PoA (not enough stuff on KCVDS to be certain of summoning Coelacanth early)
-1 Lightning Vortex (not 100% necessary like other cards here)
-1 Terraforming (only need 1 with the lineup you're using)
-1 Star Blast (Mausoleum will probably work better. I just gave this as an optional thing to try if you had space in the deck.)
-1 Water Hazard (again, this was only for if you had space in the deck.)
-1 Water Art
-1 Dustshoot (only run it when you have extra space in a deck. It's a good card, but almost never a necessary card.)

+1 Big Wave small Wave
+1 Mausoleum
+1 Bottomless Trap Hole (this should be run in 2's before you even think about running cards like Mirror Force. Hitting a monster when it's summoned is better than waiting for it to attack, because DAD, JD, Lyla, Breaker, and many others can destroy your traps before they attack.)

EDIT: I also just noticed that your synchro lineup is just awful. You're missing many of the more powerful synchro monsters. Try something like this instead:

1x Chimeratech Fortress Dragon (Cydrag at 2 this format warrants this)
1x Catastor
1x Goyo Guardian
1x Brionac
1x Black Rose Dragon
1x Ancient Fairy
1x X-Saber Urbellum
2x Stardust
2x Colossal Fighter
1x Thought Ruler
2x Red Dragon Archfiend
1x Mist Wurm

Since your deck uses Coelacanth combos, and Coelacanth summons mostly 7/8 star synchros, your extra deck should have more copies of those higher level synchro monsters. You were also missing some important synchro monsters in general.

Thanks again

how should i summon Chimeratech Fortress Dragon

It's in there because there are 2x Cyber Dragon on the current banlist and LIGHT Machine and Cyber decks will be coming back as decks you may often see. If your opponent leaves Cyber Dragon and another Machine-type monster on the field, you can summon Chimeratech during your turn, since Chimeratech specifies he can be summoned using monsters on either side of the field.

Cool I never read Chimeratech Fortress Dragon

Now that i think about it lots of people used Cyber Dragon in the past duels.

A legendary ocean is becoming a trouble i summon 1 lv4 tuner and 1 lv4 non tuner and the field makes the monsters lv 3 and the syco lv 6

What should i replace it with.

If you're getting rid of the Oceans, I suggest replacing with a 3rd Mausoleum and a 3rd Big Wave Small Wave.

How about Star Blast over Mausoleum..?!

I have to admit this deck is looking good.

what about fish deph charge its a good choince in fish decks

edited

since its all fish i thought of putting solidarity

I don't recomand you to use star blast at all i tried the deck it works pretty fast and the solydarity good choice and its fish depth charge