My kids want another fish, we have 3 comets...but they want something different than a comet, any suggestions?

Answer 1

There are lots of great fish out there that are great for kids.

If you want something active, colourful, and easy to care for, then livebearers are your best choice. This includes:
Platies http://www.elmersaquarium.com/image_fish/01_Platy_MICKEY_MOUSE.jpg
Mollies http://www.aquariumarticles.com/articles/1555321/p_89833_black_lyretail_molly.jpg
Guppies http://www.aquariumfish.net/images_01/fancy_guppies_001_w360.jpg
Endlers http://aquariumhobbyist.com/endlerslivebearer/images/ELBhome.jpg
And swordtails http://www.wildwoods.co.uk/fishhouse/freshwaterfish/red-comet-swordtails.jpg

Mollies and swordtails are the biggest of the aforementioned fish, reaching about 4". A group of them would be fine in a 20 gallon tank or larger.

Platies are in between, at about 2.5". A 15 gallon tank is good for them.

Guppies and endlers are pretty small, an 8 gallon tank would suffice.

Make sure to always get 2 females per male. You can mix up the species, too, if you have a big enough tank.

Get lots of plants if you want some of the babies to survive - and these fish will have lots of babies :) Fun to watch!

Just FYI, they cannot be kept with comets. Comets are big, waste producing goldfish that grow to 18" and need to live in ponds. These livebearers are small fish that need heaters (as do all commonly available community fish - 78F is a good water temp for them).

I you don't like the livebearer idea, you could also go with a school of tetras (like neon tetras) and a male betta or a dwarf gourami.

Answer 2

The first question you must ask is how big is your tanks. Only from there can you decide what type of fish to get. You need to provide your tank size.