I have three different species of dart frogs; they're great fun, and considerably less work than chameleons. You do however, have to have some basic knowledge.
Usually, you cannot keep multiple species in one enclosure, as the Newport aquarium seems to be doing. Dart frogs have a tendency to be pretty territorial, and will stress each other to death. Think of it like keeping two adult male chameleons in one small cage. Not so good... Also, many species can interbreed, which is highly frowned upon in the frogging community. For reference, the three frogs in the first pic are D. Auratus (Green and black), D. Azureus (Blue and black), and D. Galactonus (orange back). The next pic shows D. Tinctorius.
If you are interested in getting dart frogs, go to dendroboard.com and read the caresheets. I highly recommend D. Leucomelas or D. Tinctorius as entry level frogs. Those are the yellow and black ones and the blue and black ones, respectively.
The general recommendation is that you budget at least 10 gallons per frog. You'll want to plant the tank with enough live plants to give adequate cover, and to provide breeding locations, if applicable. Most frogs don't do well above 80F, so you'll want to make sure that you can keep the tank in an acceptable range. Also, they need moisture; you'll want to keep the humidity above 80%, most of the time. If you want to get frogs, build them a terrarium, seed it with springtails, and let the tank grow out for at least a month before you get the animals. This will allow you to keep an eye on temps and humidity, and let bacterial/fungal infestations rise and fall.
To find a source for frogs, go to dendroboard and start poking around. There are probably breeders close to you. I don't know of any in the Cincinnati area, but there are a couple of good ones in Columbus.
If you have any questions, feel free to send a PM. I'll help if I can.
