HELP! F8 Puffer going down hill!

I have two F8 puffer and some platys in a 30 gallon tank. Tank is over a month old. I have a filter, heater, and a bubble wand. Temp is about 75.
I do a 25% water change every week, I treat it with tetra aqua safe and vacuum the substrate.

Ammonia: 0
Nitrite: 0
Nitrate:.25
pH:7.5

I feed my fish once day, freeze dried brine shrimp or thawed out bloodworms and the sick puffer is usually the first one to eat.

Illness & Symptoms-
I have had both puffers for three weeks and they both have been perfectly plump, bright, and nor
A behavior until about a week ago. It’s only one of my puffers that looks bad, the other is the same and all the other fish are acting fine.
The first thing I noticed was Vegita (sick F8) would swim into the slits of the filter and sit there. It scared me the first time I saw it because he looked dead, so I put my hand in and he swam off of it and was normal. He did this a few times. He has deteriorated very quickly and will just float into plants and sit there, always looks like he is dead. He is deformed with bulges and sometimes does a gasping thing. Looks like one of his gills is swollen. He won’t eat shrimp anymore but ate bloodworms the other day. I am going to make this a brackish tank soon, just need to find a place for the platys first. I attached a picture of Vegita the sick one and Lemon the healthy one.
I was told it might be parasites so I put some microbe-lift parasite treatment in the tank yesterday.
sorry so long, wanted to get all the info out I could. Please help because he was such a happy puffer for the first few weeks and would always come up and say hi when I got near the tank. Anyone see this before?

 

I have two F8 puffer and some platys in a 30 gallon tank. Tank is over a month old. I have a filter, heater, and a bubble wand. Temp is about 75.
I do a 25% water change every week, I treat it with tetra aqua safe and vacuum the substrate.

Ammonia: 0
Nitrite: 0
Nitrate:.25
pH:7.5

I feed my fish once day, freeze dried brine shrimp or thawed out bloodworms and the sick puffer is usually the first one to eat.

Illness & Symptoms-
I have had both puffers for three weeks and they both have been perfectly plump, bright, and nor
A behavior until about a week ago. It’s only one of my puffers that looks bad, the other is the same and all the other fish are acting fine.
The first thing I noticed was Vegita (sick F8) would swim into the slits of the filter and sit there. It scared me the first time I saw it because he looked dead, so I put my hand in and he swam off of it and was normal. He did this a few times. He has deteriorated very quickly and will just float into plants and sit there, always looks like he is dead. He is deformed with bulges and sometimes does a gasping thing. Looks like one of his gills is swollen. He won’t eat shrimp anymore but ate bloodworms the other day. I am going to make this a brackish tank soon, just need to find a place for the platys first. I attached a picture of Vegita the sick one and Lemon the healthy one.
I was told it might be parasites so I put some microbe-lift parasite treatment in the tank yesterday.
sorry so long, wanted to get all the info out I could. Please help because he was such a happy puffer for the first few weeks and would always come up and say hi when I got near the tank. Anyone see this before?

The best thing you can do for them is making the water brackish, to a SG of around 1.003~1.005. The platies will be fine in that salinity. Also a higher temperature would be better, around 78 degrees.

 

Well if the platys will be fine I’m going to make it brackish today. I’ll turn up the heater too.

 

Well if the platys will be fine I’m going to make it brackish today. I’ll turn up the heater too.

The salt can crash the cycle so I'd recommend going up to 1.002, then stepping up to 1.004 a week later to be safe.

 

The salt can crash the cycle so I'd recommend going up to 1.002, then stepping up to 1.004 a week later to be safe.

I’m ready to add the salt but I am getting so many conflicting ratios. I read 1 tbsp per gallon, I read 2 tsp per gallon, and 1/8 of a cup per gallon.

 

I’m ready to add the salt but I am getting so many conflicting ratios. I read 1 tbsp per gallon, I read 2 tsp per gallon, and 1/8 of a cup per gallon.

4 tsp per gallon is 1.004, so a 50% water change with that ratio should get you 1.002. You're using marine salt like instant ocean right?

 

4 tsp per gallon is 1.004, so a 50% water change with that ratio should get you 1.002. You're using marine salt like instant ocean right?

Yes, put it in a bucket with a heater and let the salt sit for a bit after I stirred it. So it’s 120tsp total?

 

Yes, put it in a bucket with a heater and let the salt sit for a bit after I stirred it. So it’s 120tsp total?

Make 15 gallons' worth so 60tsp, and replace half the water in the tank.

 

Make 15 gallons' worth so 60tsp, and replace half the water in the tank.

Thank you so much for your help