Neat I am still testing but here is what I could suggest. Too little tuners and too many sun fish, sunfish is a card you want to search for the times you altrady have a sardine otherwise it becomes usless (i can see a somehow possible combo whit leafless but it would be really hard),the broblem whit 1x tuner is that you really need them to play in the other player turn and if they get"stuck" in the banished zone you basically can't get them back, nibiru is overrated because you can't use it to syncro summon and crossout is a better replacement since you can also banish your tuner+keif and next turn they will respawn. Minairuka is a good card to have X1 when you want to chain it whit the tuners and potect your board as much as possible when you syncro summon. Other choises for extra deck are, Kraken (perfect against fusions and a good interruption),white aura monoceros (if you summon whale from gy or askaan it triggers the white reincarnation borard breaker also it makes abyss shark more useful for syncros), double whale is an Absolute blast since it's effect is not once per turn also is a good way to use psiics+snopios when you have 2 tuners, the problem whit whale is when they do all they can to not kill it soo.. make them do the effort of it all back again.Guoglim can be good if you need a cheap way to banish especially if you used psiics for it, the attack thing Is also cool but I never was able to use it.I also put deepes dephts at X2 because it's hard to get rid of, if you draw more than one and you can still play whitout it. Also double chain and 1 cosmos because LEAVE MY FISH EFFECTS ALONE. But hey what do you think?

Monster xyz? More advisable?

And coleacanth?