Okay...I'll take this species by species.
Tokay
Tokay geckos are solitary creatures. They generally have pretty...unpleasant...dispositions and can and will bite under the slightest provocation. As far as enclosure requirements they prefer a temp gradient of 76-90, 90 being under the basking spot. A temp of at least 85 is needed for most to even digest food properly. Humidity should be maintained anywhere from 70% to 90% and should never drop below 50.
Green Tree Frog
I can only assume that the unknown green tree frog is in fact Hyla Cinerea. They are very skittish frogs. Ambient temps for them should only be around 75 to 78; 78 to 80 in the basking spot. Night time temps should never fall below 70. Humidity should be maintained at 30 to 50 %
Cuban Tree Frog
First and foremost, these frogs have toxic secretions. Temps should be 80ish in the day, 70ish at night. High humidity at 70% to 90%. Cuban tree frogs are notorious cannibals, and will eat or attempt to eat their smaller tank mates. Females can reach 5 inches or more, so your grays and greens will be fair game.
Gray Tree Frogs
Kept primarily as Greens, but they do need a moist substrate. They can tolerate temp. fluctuations, but they shouldn’t have to. They should be kept at around 75 to 80 degrees.
Common Toad
Toads need moist substrate to burrow in, period. Hiding is what makes them feel safe. They will also eat tank mates whenever presented with one that will fit in its mouth.
Problems with Your Enclosure (other than the obvious species mixing)
The chip substrate that you are using is an impaction waiting to happen.
Your water dish is not healthy, PERIOD. Cubans have secretions that are toxic to most other animals. When it soaks, it contaminates the water. Then when your others go to use it, they are absorbing toxins introduced by the Cuban.
Your tank looks mighty cold. I do not see any overhead lamps at all in the photo, and with arboreal species, an undertank heater is useless. Where is the temperature guage?
It also looks mighty dry. The dishes are useless to the Gecko, and the substrate you are using isn't exactly ideal for holding moisture to maintain the humidity. Where is the humidity guage?
Most of the captives you have are wild caught. This means you have no idea what pathogens and parasites they have already or will expose the rest of the tank mates to. Once one gets ill, or succumbs to the stress of living in a tank like that, that particular animal’s immune system will start to falter. Those parasites which were once kept in check by the healthy immune system will boom out of control and eventually take the life of that animal and possibly more through enclosure contamination.
Conclusion
If in fact your tank has been operational for 2 years, than now is the time to do right by your animals. They are not "happy". They are incapable of feeling happy. They feel either safe or unsafe. Unfortunately for you and ultimately them, those animals are not safe in the least bit. I will assume that you didn't do a whole lot of research before you got them, and you probably have seen mixed tanks in various pet stores and zoos. Well pet store mixed tanks fail, they just have the money to replace the animal or they either tell you or you assume it was sold. Zoo enclosures also not easy to keep, that I know from experience as I work at one. Lucky for the zoo, they can afford huge tanks to have arboreal and terrestrial species separated. And once again, casualties can be replaced before anyone even notices.
All of your animals need enclosures specific to species ASAP. They are alive, but they cannot thrive in an environment like that. It is not fair to them, and if for some reason you do not have the funds or space to facilitate that move than you really should consider finding replacement homes for some of them. That doesn’t make you a bad person, just one in a bit over your head. Pick your favorite, redesign the tank, and relocate the rest. I'm not trying to condemn you, it's a common mistake and unfortunately most people just don't know any better. Now you know. No one here is trying to blow smoke up your butt. We just want what is best for the animals. You can email me personally if you'd like help, or you can let them survive like that and wonder why they start to drop off like flies one day. I t is your choice. We just hope that you make the right one.
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*~~Whitney~~*
There are two types of people in this world, good and bad. The good sleep better, but the bad seem to enjoy the waking hours much more.