4 Pokemon Communication
4 Rare Candy
4 Junk Arm
4 Pokemon Collector
4 Professor Oak's New Theory
4 Double Colorless Energy
4 Rainbow Energy
6 Water Energy
Blastoise is the heavy hitter and main attacker of the deck. It can hit anything for 100, including the bench, but then must return 2 water energy to your hand. That's where floatzel comes it. It allows you to attach extra energy per turn to re-power up blastoise. Since they're both weak to lightning, your counter is donphan, a pokemon that can KO most lightning types in one hit with just a single fighting (or rainbow) energy attached.
With pokemon catcher being used to KO basics early, I'd recommend that you add in another squirtle. Since you only need 2 floatzel set up, you should be safe with a 3-3 line. I'm tempted to increase your donphan line to 3-3 since lightning is one of the biggest decks around right now (Eelekric variants). This will ensure that even if you have part of your line prized, you'll be able to recover. While I love manaphy, I think to make your deck more consistent, it's safe to drop and just stick to a single cleffa.
I might consider reducing your DCE down to 2 and increasing your water. Or just use those 2 extra spots for something else. If you have 2 floatzel, you'll be able to attach 3 energy per turn which means that you may not always need your DCE (it's just nice in getting a fast start). I'd love to find room for rescue energy in case your floatzels are KO'd, but I just can't think of how to fit them in (while Donphan is a great tech, you really need the 4 rainbows for it).
The two cards that I'd really like to see in this list are pokemon catcher and a super rod. Pokemon catcher (possibly 2 of them) will allow you to drag up something that has a heavy retreat to stall while you snipe around it. I like one recovery card in every deck just to get those water energy and any pokemon you might need back into the deck. If you decide to stick with a lower donphan line, having a super rod to put it back becomes even more important. You might be able to benefit from the addition of N as well. Once you get your floatzel set up, you can survive off the field. So reducing your hand down to only a few cards won't hurt you, but could really devastate your opponent. To make room for these suggestions, I think you can safely go down to 3 twins, and possibly reducing the PONT line (especially if you're including a couple of N). Since blastoise is your only stage 2, you should be able to reduce your rare candy count to 3 and possibly your communication count to 3 as well, especially with twins to help find them.
It looks like you already have a pretty great deck, especially with the donphan tech to counter your decks main weakness - lightning. Hopefully trying out some of my suggestions will help it run even better! Thanks for submitting!