Post-mortem platy tank treatment

[Analog Kid]

Late last night, I noticed that one of my silver crescent platys was in trouble - its tail fin was ragged and it had brownish-red spots on its body, and its skin appeared milky in spots. I did some research and decided that it was a combination of septicemia and fin rot, and that I'd pick up some antibiotics this evening. Unfortunately, the poor guy didn't make it through the night.

This morning, I gave all the remaining fish a close look. One of the other platys appeared to have a single brownish-red spot - so now I'm paranoid that whatever it had is contagious. So, I have two questions:

1) Does my diagnosis of septicemia/fin rot sound correct?
2) What should I do to make sure the other fish don't catch it?

Tank stats: Up and cycled for a few months; I've only had fish for about one month, starting with the tetras (~1" each), which still look OK. The platys (~1.5" each) have been in residence for a week, and all appeared healthy until last night. No new decorations for 3 weeks; last water change was 25%, with last week's vacuum; I'm on a weekly vacuum/change schedule. AquaClear 200 filter @ 200 GPH; partial media change 2 weeks ago. Chemistry as of last night was:

Ammonia 0
Nitrite 0
Nitrate 20
pH 6.0

The pH was at the lower limit of my test kit, so I added a little pH-Up...I'm trying to balance it between the needs of the tetras and the platys.

Thanks!

 

[Candice]

Platy's prefer a ph of 7.3 or so.

The acidic water could be causing problems.

Also, are you using salt in your water?

Livebearers tend to need some salt in their environment...1 tbsp/5 gallons of water.

 

[Analog Kid]

No salt - I'd seen conflicting opinions on it, but I can add some tonight.

 

[Menagerie]

[center:10f2cee726] Welcome to AA, Analog Kid!! [/center:10f2cee726]

1) Does my diagnosis of septicemia/fin rot sound correct?

Does it look like the fish are bleeding under the scales?

2) What should I do to make sure the other fish don't catch it?

Do you have a QT tank?

What is the pH of your tap water (allow a glass of tap water to sit out overnight and then test)?

The pH was at the lower limit of my test kit, so I added a little pH-Up...I'm trying to balance it between the needs of the tetras and the platys.

A stable pH is better than a perfect pH. Those fish can all live happily from pH 6.8-8. After you add the pH up, what is the pH? The next day, what is the pH? I ask because pH swings cause stress to the fish and make allow diseases to infect quickly.

What size is the aquarium? What substrate are you using? Is there any rotting matter in the tank (excess food, plants)?

You should add some salt to help the fish along while they are ill. After that, it's up to you.

 

[Analog Kid]

[center:d7970d33d9] Welcome to AA, Analog Kid!! [/center:d7970d33d9]

Thanks!

Does it look like the fish are bleeding under the scales?

Kind of...I think the medical term would be "petechiae", more like isolated spots of blood.

Do you have a QT tank?

No - this is my first experience with sick fish. I had been going to pick one up tonight to treat the sick one, if he was still around.

What is the pH of your tap water (allow a glass of tap water to sit out overnight and then test)?

A stable pH is better than a perfect pH. Those fish can all live happily from pH 6.8-8. After you add the pH up, what is the pH? The next day, what is the pH? I ask because pH swings cause stress to the fish and make allow diseases to infect quickly.

I'll check again tonight. I usually don't adjust it, but I got paranoid when I saw the sick one.

What size is the aquarium? What substrate are you using? Is there any rotting matter in the tank (excess food, plants)?

29 gallon tank. A little extra food - it's time for the weekly vacuum. Substrate is medium gravel (largest pieces are around 1/2"). No live plants.

You should add some salt to help the fish along while they are ill. After that, it's up to you.

I'll definitely pick up some salt tonight. If any of the others look sick, I'll go ahead and buy some Maracyn 2 and a QT tank as well.

 

[Menagerie]

I really like kanamycin based meds for treating septicemia, as it can be added to the water and/or food. Seachem makes a product called Kanaplex. Make sure the salt is aquarium grade, not marine grade and dissolve it in some water before adding to the tank.

Sounds like you may be over feeding. Feed at most once a day, or even every other day. With that sized gravel, uneaten food can get down to the bottom and rot away.

 

[Analog Kid]

Update:

Looks like the other fish are fine, for the time being. Whew!

I added aquarium salt (1T/5 gal) last night, and am cutting back to 1 feeding per day.

I'm a little concerned about my pH behavior, though...the tank's still at 6.0 or below, even after adding the pH-Up. My tap water tests at 7.4 after sitting 24 hours, and I did a 33% change last night...so it looks like something in my tank is really dragging it down.