Colu

I think your water parameters are the cause your pH is to low for guppies 7-7.5 is beat your KH GH are to low that can lead to a lot of health problems with Guppies they can essentially start to fall apart due to lack of minerals and the small amount of ammonia you have could have caused the Redding you want a KH between 4-8 and a GH of 6-8 what i would do is add crushed coral to your substrate or in media bag in your filter you need 1 pound of crushed coral per gallon to raise your KH and GH you could also add some wonder shell in the short term to add some extra minerals till you can increase your KH and GH @MidnightBel

Looks like he's swim into something possible a piece of wood and stab it's self I would monitor it might heal on it's own with stable water parameters and add a small amount of aquarium salt 1 table spoon for 10 gallons that will aid Gill function and add essential electrolytes if you notice any Reddening or fuzzy appearance to the wound then I would quarantine and up the aquarium salt 1 table spoon for 2 gallons and do a course of kanaplex @Milliardo Peacecraft

Epsom salt acts as a muscle relaxant to help with constipation aquarium salt doesn't work as a muscle relaxant You can add Epsom salt to your tank if you done want to do a it as a bath it will raise GH so I would do 1 table spoon for 3 gallons for 5 days and go from there

As most puffers are wild caught and suffer from a heavy parasite burden I would treat following @Odd Ducktreatment protocol for parasitic infection levamisole and praziquantel shouldn't harm juvenile puffer i would feed at least once a day during

Scales stick out live a pinecone

I would start by doing epsom salt baths 1 table spoon for 1 gallon for no more than 15 minutes for 5 days as could be constipated or he could be bloated due to underlying issue such as kidney failure have you notice any pineconing @Bigdog99

A little more information would be helpful what are your water parameters ammonia nitrite nitrate pH KH GH temperature any loss of appetite rapid breathing @yakteriyaki

If you can try and get a better picture have you notice any changes in behaviour such loss of appetite rapid breathing hanging out near the surface separating it self from the group loss of colour

Your charts fine the only thing I would do is add active carbon after your 50% water change to remove any remaining medication before treating with paracleanse I haven't had any issues with my beneficial bacteria when using anti-parasitic medication such levamisole praziquantel one active ingredient in paracleanse metronidazole does effect gram negative bacteria I haven't have any issues when using it I would just test more often while treating I wouldn't be concerned

It's poop without any food in it just the mucus lining nothing to worry about

Just leave the light off for 24hr during treatment

If you can get a picture it With a diagnosis

If it's a difficult one when you have multiple things going on I would do one course of API fin and body cure if he's still here when expel p arrives start treatment straight away it's a 24hr treatment once a week for 4 weeks leave I low dose of salt in it will aid Gill function and add essential electrolytes That doesn't look like epistylis it's more typical of an external bacterial infection that cause tissue and possibly Gill damage

That fish is looking emaciated it could have been weaken by the parasite then developed a secondary bacterial infection what I would do start treating with expel p once a week for 4 weeks and i would use antibiotic treatment with a different active ingredient api fin and body cure or maracyn2 which every one is more readily available

Cupramine is a copper based medication using some medication with copper can alter the bond making them toxic if using antibiotics in food that's less likely to happen Polyguard has multiple active ingredient it can treat bacterial fungal and some external parasite's I wouldn't use for fin rot it's a more harsh medication maracyn2 or kanaplex would be a better choice paraguard say it treats fin rot but looking at the active ingredient i don't think it would be very effective

I would us maracyn2 or kanaplex and dose the tank to treat fin rot if am using other medications such as cupramine I would do a course of maracyn2 in food feeding a small amount twice a day for 7 days @Tony s

I wouldn't recommend using kanaplex in food very little of medication is adsorbed by the intestinal tract so not much of the medication makes it into the blood stream your better of dosing the tank if your using kanaplex

If your water parameters are fine it Could be constipated I would try fasting for a couple of days and do an epsom salt baths 1 table spoon for 2 gallons for no more than 15 minutes for 5 days give an update in 5 days if he gets worse before then @Goosedub

Possibly a gold nugget pleco if I remember rightly they do lose the yellow on the edge of the tail fin another guess would snowball pleco

When they spit food out it's usually due to the irritation of the throat caused by a parasite I would keep treating with expel p I would try offering live or frozen brine shrimp daphnia blood worms if you aren't already doing that to try and simulate his appetite

You could swap them if it were neon tetra disease I would quarantine and not put them in with other fish as NTD can infect angelfish danio rasbora barbs guppies other species of tetra there's no treatment I would leave it week to see if it is the start of NTD before switching them it could just be a mouth injury i always air on the side of caution with neon tetra it seems to becoming more prevalent

Looking at the pictures I don't think treating with maracyn2 I recommended would have any effect in one of the pictures it looks like the mast is on one side if so it more likely to be a cancerous or benign growth treatment wise your opinion of limited if you think she suffering I would Humanely euthanize her with clove oil

Wild neon tetras come from black water with a low bacterial count they are more susceptible to bacterial infections the one with the pointed could be caused by a parasitic infection if you if you haven't seen any rapid breathing hanging out near the surface lethargy spitting food sunken belly flashing i would monitor the Possibly the start of a snout chondroma on the mouth that's caused by neon tetra disease i can't say for sure that's the cause 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 monitor for two weeks give an update if they get worse @Ashley O

Levamisole can be harmful to some types of snails so it's best to remove them

I can see something but with the cloudy water it's difficult to see what's going on possible cancerous or benign growth with what your describing there's not a lot treatment wise I could recommend you could do a course of maracyn2 active ingredient minocycline has anti-inflammatory properties and fast for a couple of days see if she improves if you can try and get a better picture that will help with a diagnosis