I spoke with Criminal Science Ichthyologist Agent Tisha last night about the untimely demise of my two fantails. She gave me some advice. We drained the pond, hosed off the rocks, and refilled it with fresh water -- no sign of Spot the entire time, so either he's croaked behind a rock, been eaten by a neighborhood predator, or killed and eaten by the now-deceased Fluffy.
At lunch today I made another run to the petshop and picked up a trio of plain ol' Comets -- the generic brand of goldfish. Together, they set me back thirty cents. Each fish is just under two inches long. The petshop girl told me I could easily try three at this size, and that would encourage survival of the fittest. At ten cents each, it's hard to argue that logic.
The petshop girl was really funny. She dipped the beautiful bright orange fish out of the feeder tank, and picked the biggest, most vigorous, healthiest-looking Comets out of the hundreds of other fish. She even put a couple back because they looked a little pokey. The final trio were giving her a hard time getting into the bag, and she kept mocking them -- "Ease up, stupid fish! You're going to Fishy Paradise! Everyone else in this tank is gonna get eaten!"
I also took Tish's advice and bought a Litmus Test Kit. I put the fishbag in the water to get acclimated, then tested the water. I now know what killed at least Fluffy, and probably Spot -- the PH was up over 8.5! Yikes! I knew we had hard water, but holy cow. I dumped in about a cup of white distilled vinegar in stages, checking between additions, until the water was at a nice 6.5 - 7.0 ... I added a little more vinegar than I probably needed, figuring that the rocks will continue to leach into the water, making it more alkaline over time.
I haven't named these three yet, as they're all pretty much identical. One's a little lighter orange than the other two, but other than that, they're all the same. I will say this -- they're certainly more speedy and vigorous than the two fantails, and according to Tish and the petshop girl, the comets are way hardier, too.
So yeah. Fish. Yay, fish. Yay, Tish.
I sense a Dr. Seuss coming on...
Yay fish yay.
Yay Tish yay.
Tish loves fish
who live in Mich.
I'm sure there are dozens of other verses out there somewhere. As for names, I'm assuming you've gone through all of the usual triplets - Larry, Curly, and Moe; Huey, Dewy, and Louie; Larry, Darryl and Darryl; for our three oclock break here we just came up with some others:
Shana, Nana, and Noonie
Before, During, and After
Dick, Jane, and Susan
Three, Dog, and Night
Creedence, Clearwater, and Revival
Kung, Pao, and Chicken
Fried, Poached, and Grilled
Sugar, Ray, and Leonard
Tony, Toni, and Tone
Bel, Biv, and Devoe
Rock, Paper, and Scissor
OK, we'll stop now...
Sushi, Sashimi and Maki
What about:
Ku Klux & Klan (now you can legally drown the Klan)
Kwik Kwek & Kwak (or Huey, Dewey & Louie?)
Pim Pam & Pet
Larry Moe & Curly
Harpo, Chico & Groucho
Diana, Florence & Mary
Dolly, Linda & Emmylou
The Father, The Son and the Holy Spirit
Liberté, Egalité & Fraternité
Nina, Pinta & Santa Maria
Yay me!
I'm glad my brain managed to finally noodle around to a solution for ya. Good luck with the new trio, whatever you end up calling them. 
Oh, and because I was an avid swimmer when I was little, one of my nicknames used to be Tish the Fish, or just Fish. So, you know ... I'm sure Suess would have loved it.