Hi Steve and welcome to the forum
The M. boesemani are probably not the best choice with the other fishes. The males can get big (4 inches) and boisterous. They usually leave other fish alone but I have seen two inch long boesemani eat one inch long cardinal tetras. If you have a couple of males that are the same size, they normally display to each other and show off to the girls and then they are fine with other fish, but watch them.
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What are the tank dimensions (length x width x height)?
What is the
GH (general hardness),
KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg:
ppm, dGH, or something else).
The boesemani and platies so best in water with a
GH around 200ppm and a pH above 7.0.
The other fishes you have come from softer water with a
GH below 120ppm and a pH below 7.0.
Adult Melanotaenia boesemani need a tank that is at least 3 feet long and 4 foot long or bigger is better. They need lots of plant matter in their diet and a least half their diet should be plant based. You can use vege flakes and pellets as part of their diet but live aquatic plants should be used too. Duckweed (a small floating plant) was taken by all of my rainbowfish.
The following link has information about Australian and New Guinea rainbowfish and might interest you.
Melanotaeniidae and Pseudomugilidae
Rainbowfish and dwarf gouramis regularly carry Fish Tuberculosis (TB). Dwarf gouramis regularly carry the Gourami Iridovirus too. Rainbowfish are very prone to Fish TB due to never being exposed to the bacteria until about 30 years ago when rainbowfish started appearing in the hobby. Common symptoms of Fish TB is ulcers and or gill tumours, then a few months later the fish might bloat (get fat) overnight, stop eating, do a stringy white poop, breath heavily at the surface or near a filter outlet, and die within 24-48 hours of showing these symptoms. Confirmation of Fish TB is done by a necropsy (animal autopsy) by a vet. There's no treatment for Fish TB and some rainbowfish are fine and don't have it, but it is out there so monitor your fish for the above symptoms.
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The emerald green Cory should be kept in groups of 6 or more. You can sometimes get away with 4 but there should be other Corydoras they can hang out with.
The Iriatherina werneri rainbows should be kept in groups of at least 6. Try to have even numbers of males (2, 4, 6) and some females.
The platy could do with some friends (it's not majorly essential for them but they do like company). If you get a couple more try to get the same sex as you currently have.
Frogs should be kept on their own for 2 main reasons.
1) If the fish get sick, any medications used to treat them can kill the frogs.
2) Frogs eat small things like fish, shrimp and snails.