Colu

Can you get a better picture of the fish with something on its mouth

You can do use paracleanse one of the active active ingredient praziquantel that treats tape worms flat worms and flukes were as expel p active ingredient levamisole treats nematode worms hook worms nodular worms roundworms looking at the picture I would start treating with expel p what you could do is @Odd Ducktreatment protocol for parasitic infections using paracleanse instead of prazipro @macdaddy36

Sunken belly and hump back can be a sign of wasting disease for that you would want to treat with levamisole active ingredient in expel p have you notice any rapid breathing hanging out near the surface lethargy spitting food flashing what are you feeding and how often @macdaddy36

Seachems cupramine if I remember rightly has to be dosed every 48hr just follow instructions on the bottle

I would Also add 1 table spoon for 2 gallons of aquarium salt as ich causes massive electrolyte loss and the salt adds back in essential electrolytes

His fins aren't looking to bad in the video I would leave the salt at the level it's at for another week then water change it out and just leave the almond leaves and monitor for the next couple of weeks for any Reddening to the edges of the fins or receding or holes developing in the fins

Looks like epistylis it feeds off of gram negative bacteria on the slime coat and spreads more quickly at higher temperatures the most effective treatment is a course of maracyn2 in food and ick X or you can use aquarium salt 1 table spoon for 2 gallons if he's not eating i would dose the tank with maracyn2 he's how you tell the difference between ich and epistylis @CozyReign

In wild pea puffers live in large groups a group of six in a 20 gallon would be better long term if you add them all at the same time

Its difficult to tell if it's swollen keep treating with maracyn and aquarium salt that will help with possible eye issue @Fish Enthusiast

I wouldn't use methylene blue in your tank it will kill your benefial bacterial the best treatment for ich is malachite green active ingredient in most ich medication such as ick X and aquarium salt 1 table spoon for 2 gallons as ich causes massive electrolyte loss and the salt adds back in essential electrolytes and add an extra air stone during treatment

It can take upwards of 4 weeks in some cases

Looks like egg spots some male African cichlids get them

How big are the caves if they are to small they can injury there head while trying to trap the female or fighting with another male for a cave

Could be columnaris that's a gram negative bacterial infections that spreads more quickly at temperatures over 75°f and can kill in 24hr to 7 days for the cold water stains the most effective treatment I have found is a combination of kanaplex and jungal fungus clear fizz tabs containing nitrofurazone following this treatment protocol @Elyse

It Could be bacterial or viral as other have mentioned I would do a course of maracyn2 or kanaplex both are broad spectrum antibiotic treatments and add an extra air stone during treatment @Finding NiMo

It could have a different amount of the active ingredient that's why the dosing is different

I would do a large water change then dose kanaplex after the full course of kanaplex do a 50% water and run active carbon for 24hr to remove any remaining medication

It's a species of synodontis you can also get hybrids from Asia so it no always the easiest to identify to species level

Is there anything in tank that he could be injuring himself on

Malachite green and formaldehyde should be fine for your Cory's and Otto's at the recommended dosage on the bottle with ich medication it always recommends a half dose for sensitive fish that doesn't successfully treat ich I have used medication containing those active ingredient with bristlenose and Cory's at full dose without issues what I would do is a large water change and add carbon for 24hr to remove any remaining medication then start treatment with your ich

These a couples of treatment for ellobiopsidae one malachite green active ingredient in ick X or you can use a 3% hydrogen peroxide solution

With the symptoms your describing you could have two things going on curved spines and weight loss can be sign of a parasitic infections the bulging eye and lethargy could have a bacterial component what I would do is a course of kanaplex and add some aquarium salt 1 table spoon for 5 gallons that will help reduce fluid buildup in the eye it won't harm your clown pleco I have used kanaplex with bristlenose I had not harmful effects I no people who have treated other species of L number plecos without having issues then I would follow up with a course of expel p active ingredient is levamisole once a week for 4 weeks so do a large water change through gravel vac that will remove parasites eggs from the substrate add the medication blackout the tank as levamisole is a light sensitive medication in 24hr do a water change and through gravel vac and repeat on week 1 week 2 week 3 week 4 and add any extra air stone during treatment @AquaticTurtle

With the symptoms you described I would say they were killed by a bacterial infection or viral infection what I would do if you don't have it to hand is get kanaplex or maracyn2 both are broad spectrum antibiotic if you start to see any of the same symptoms start treating straight away

Guppies can flash if your pH KH or GH are to low if there's ammonia in the water or chlorine if you don't use a dechlorinator through a parasitic infection such as ich or flukes most fish will occasionally flash once in a while it's if it's happening multiple times a day it's more likely to be caused by one of the above causes if it's once every couple of days less likely to be a parasitic infection @Mercfh

Your new fish could have had a parasitic infections even if they infected your other fish they wouldn't have died with in three days it can take a couple weeks to months in some case from point of infection for a parasite to kill your fish with mass mortality over a couple of days i would be learning to problem with your water parameters ammonia nitrite or a fast acting bacterial infections what were your water parameters at time of the deaths and what symptoms were you seeing in the fish that died @only6foot6