Just a heads up, bigger is not always better when it comes to darts. Yes, you need to culture fruitflies as the staple of the diet. However, with something like a 240 gallon tank, you run the risk of frogs not being able to find food unless you cover it in flies every feeding. There are ways around this, but a 240 gallon is definately a difficult thing to do, especially if you're new to darts.
0.4.3 D. leucomelas
0.1.0 D. imitator
0.0.3 D. tinctorius 'Alanis'
1.1.0 D. tinctorius 'Surinam Cobalt'
1.1.0 D. pumilio 'El Dorado'
1.1.0 D. pumilio 'Golddust Bastimentos'