Colu

Possible lymphocystis that a viral infections no treatment available the the nodules may spontaneous disappear after a few weeks provided the water conditions are good and the fish gets the best possible care recovered fish may have some resistance to the disease I can't say for sure that's the cause there could also be a bacterial component what i would do is add aquarium salt 1 table spoon for 2 gallons and do a course of kanaplex with aquarium salt just remember to put back in what you take out so if you do a 2 gallon water change put 1 table spoon of salt back in as salt only removed though water changes and add an extra air stone during treatment black patches on the fish are indicative of ammonia burn so I would keep a very close eye on your water parameters@John Tremper

I would only use the multi cure as ichonex has one of the seem active ingredients malachite green am assuming your in Australia you can get blue planet aquari-cycline antibiotic treatment that would be my go to choice of treatment I would treat with multi cure till you can get blue planet aquari-cycline @Lily Beth

Am going to tag@Fish Folkbreed rainbow shiners has. Lot of useful information on them

Forgot to add Paracleanse is safe to use with your shrimp in the tank

My bristlenose get this it's usually rubbed when a trapping occurs I leave it a lone and it always heals with out any need for treatment

Some species of Chaetostoma have orange fins I have seen one species with a half orange body I can't remember the name of that species of the top of head

I wouldn't use oil based medication like pimafix and Melafix it can be harmful to Bettas labyrinth organ as @Tony s recommended I would treat with a broad spectrum antibiotic treatment such as kanaplex or maracyn2 and I would add some Indian almond leaves as they have antibacterial and antifungal properties you might have to add one leaf per gallon to get a beneficial effect and i would add some aquarium salt 1 table spoon for 2 gallons that will aid Gill function and add essential electrolytes help with any potential fungal infection that could be going on just keep a close eye on your water parameters during treatment @Lily Beth

Looks like a species of Astyanax if you no the exact location were you were it shouldn't be difficult to narrow it down

Your water parameters look fine they could just be stressed and trying to hide

First I would gradually raise the temperature to 82 betta and add a small amount of aquarium salt 1 table spoon for 5 gallon that Will aid Gill function and add essential electrolytes I would do a course of kanaplex most of time when Bettas get weak it's because there immune system compromised due to inbreeding and poor condition at the fish farms and store when there kept in small cups could be bacterial infection kanaplex is a broad spectrum antibiotic treatment I would do a course then give an update if your seeing no improvement or he gets worse @Jaydela

Prime can Lower dissolve oxygen for short amount of time if over dosed I use a dropper and use 1 drop per liter when doing water changes and base dose my tanks and haven't had issues sunken belly and spitting food out can be a sign of wasting disease for that you would want to treat with expel p active ingredient levamisole once a week for 4 weeks and black out the tank during treatment as levamisole a light sensitive medication and do a good gravel vac 24 HR after treatment to remove as many expelled parasite and eggs from the substrate as possible add an extra air stone during treatment

It could be parasitic infection or he's really stressed in his new environment given the fact it's been a week I would have expected him to have started eating normally by now what I would do is 3 course of paracleanse two weeks apart following the instructions on the box so treat on week 1 week 3 week 5 paracleanse could harm your benefial bacterial as one of the active ingredient metronidazole treats gram negative bacterial infections such as aeromonas I haven't had an issue do more frequent testing for ammonia and nitrite during treatment add an extra air stone during treatment

Did they have sunken bellys before they died or after as fish decompose really quickly in warm water so what you could be seeing is post mortem changes have you notice any rapid breathing hanging out near the surface spitting food out also when you do a water change do you use a dechlorinator like prime @Sondra Bradshaw

Clamped fins can be a sign something off with your water parameters or disease your KH is to low for platys they like a KH of 80ppm - 160ppm I would add some crushed coral to gradually raise your KH you want to add 1 pound of crushed coral per 10 gallons low KH can cause a lot of health issues with liverbears @fishnub

Have you notice any rapid breathing hanging out near the surface lethargy flashing spitting food out white stringy poop @Sciurus

Esha ndx active ingredient is levamisole that's readily available in the UK

Yes tank water fine to use. You want 1 gallon of tank water and 1 table spoon of epsom salt I usually add it to a small container or bucket @Cjbear087

Could be a cancerous or benign growth bacterial infections can cause growth if it's not got a fuzzy appearance I would do a course of a broad spectrum maracyn2 active ingredient minocycline also has anti-inflammatory properties given an update after 5 days if your seeing no improvement@Dave Spangler

Yes and give your tank a good gravel vac 24 HR after treatment to remove as many expelled parasite and eggs from the substrate as you can

Treat the main tank as all your fish will need treatment it's only when you get a high parasite burden that you see the red worms protruding for the anus it when it gets to that point your fish can have internal damage causes by the parasite when treating with expel p you want to black the tank out for 24hr during treatment as levamisole is a light sensitive medication and add an extra air stone during treatment@Cjbear087

Could be a snout chondroma that's caused by neon tetra disease he's a picture for comparison or it could be a cyst if it were a cyst you would want to treat with aquarium salt 1 table spoon for 5 gallon at that level most plants are fine @ScaperGirl

Looks like camallanus worms they can cause prolapse as your fish struggle to pass the parasite the most effective treatment is levamisole active ingredient in expel p treat once a week for 4 weeks you can do Epsom salt baths 1 table spoon for 1 gallon for no more than 15 minutes for 5 days as Epsom salt acts as a muscle relaxant to help your fish reabsorb the prolapse @Cjbear087

I have a hygger 10 watt adjustable air pump that would work it can run six sponge filter not loud

1 table spoon for 5 gallon of aquarium safe for your Otto

What's your ammonia and nitrite level and if possible a better picture it will help with a diagnosis