for now its the bettas, they have lived the longest with me (since august of last year, almost 1 full year now!) and are extremely easy to take care of. unfortunately, i had to house them in 2 1.5 gallon acrylic unheated tanks for a couple of months before moving them into a 10 gallon heated aquarium. i noticed the incredible change, much much more active and healthy looking, heat does wonders for them! one of the bettas is even brave enough to jump out of the water to grab the pellet out of my fingers when im feeding them. very fun to watch the two attempt to battle it out between the dividers. (can't see each other now, its covered in thick algae!)