Pegasus is found under the Tank Mates section of the store. It can be named, but its gender is not made clear. We’re guessing from the pink hair, it would most likely be a girl, but that can be changed by simply giving it a boy’s name. Either way, you can purchase the animal for 66 Pearls or 55 Facebook Credits, or the equivalent of $5.50 US.
Meanwhile, the Fireflies are found in the Decorations tab of the store. You buy the Fireflies individually for 1,550 coins each. As a decoration, they are purely a decorative item, meaning that gender or name customization is out of the question. The Firefly, once placed, will fly around in circles and the bulb on its tail will light up.
Neither of these items are marked as limited edition, so we’re guessing that they’ll be around for either an extended period of time, or permanently. Make sure to head over to the game’s page to purchase either of them.