Red Gills Suddenly - Treatment And Tank Help

  • #1
HI all.
This is my first post and I have tried reading lots about parasites and red gills but I'm worrying about a few specific things. I'm very new to fish keeping but I'm trying my best and hope you can help.(situation described at bottom

What is the water volume of the tank?
200 litres

How long has the tank been running?
3 days (transfered from established 87 Litre tank along with established filter)

Does it have a filter?
Fluval 206

Does it have a heater?

What is the water temperature?
26* Celsius

What is the entire stocking of this tank?
1 female guppy with 5 fry
2 bristlenose pleco
9 neon tetra
4 blue dwarf Rainbowfish

How often do you change the water?
25-30% weekly

What do you use to treat your water?
ApI tap conditioner
Kh and Gh crystals to get them to 8 (tap water here is 1 degree for both)

Do you vacuum the substrate or just the water?
Some of the substrate, but this is a new tank

*Parameters - Very Important
Did you cycle your tank before adding fish?

What do you use to test the water?
ApI test kit

What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0
Nitrite: 0
Nitrate: 0
pH: 6.8 or 6.9

How often do you feed your fish?
2x daily for 15 to 20 seconds (one day fasted)

What brand of food do you feed your fish?
Frozen blood worms (1x per week)
Other days are nutrafin max flakes

Illness & Symptoms
How long have you had this fish?
About 7 weeks

How long ago did you first notice these symptoms?
2-3 days ago

In a few words, can you explain the symptoms?
Red gills on almost all fish (pleco have red mouth and chest)
Only the guppy is flashing
No other symptoms yet

Have you started any treatment for the illness?

Was your fish physically ill or injured upon purchase?

How has its behavior and appearance changed, if at all?
Only red gills

Explain your emergency situation in detail.

**I had an 87 litre tank set up for about 2 months which I believe had bad water quality - I kept getting sick fish (mostly guppies) and believe the bad water was because I did not clean the water properly after cycling which involved rotting plants and fish waste (I briefly had feeder fish in before returning them).

The recent problem started with the plecos who suddenly had red mouth and chest 1 week ago after I returned from a 2 day trip (they were not fed). Since then I set up a 200 litre tank 5 days ago) with all new water which has the exact same water parameters as the old tank as well as the old filter (fluval 206), I also let the water sit for a few days. I moved the fish over yesterday. It was just after moving that I noticed almost all the other fish have red gills.

The gills are not bleeding and I se no visible mucus or hairs but I'm lead to believe it's either bacterial or flukes. Ammonia is and has always been 0ppm.

The fish all act normal except the guppy occasionally flashing on her gills. This makes me think it's early stage.

I'm worried I messed up and contaminated my new tank as well? I DO NOT want to medicate the main tank as it's all new clean water and I don't want the medication Staining it.

In Australia so immediate choices for meds are limited in my area but I have a formula of malachite green and formaldehyde I could use.

I'm thinking leave the fish in the main tank and hope the good water helps them OR move them back to the old tank after a water change and medicate them.

Any help is very appreciated, thanks.
  • #2
Okay, first off welcome to fishlore! We'll do our best to help you here.

Starting off, your tank is not cycled yet. If you set up your old tank the same way you set up this one, that is why you were having sick fish. Though, usually the red gills and difficulty breathing is an ammonia spike and if your ammonia is reading 0, then that's not what is happening here. Red gills is a sign of oxygen deprivation either due to chemical inhibitors OR physical debris. Either there isn't enough water movement (enough oxygen) in the tank for all the fish, or there is something in the tank that is....getting 'stuck' in their gills and stopping them from processing oxygen. Are you sure ammonia is at 0? Are the fish at the top of the tank opening and closing their mouths?

you seem to have a good filter, and generally the filter will put enough oxygen into the tank to sustain everyone so, this is a bit odd.

To start off though, cycling the tank takes anywhere from, 4-6 weeks on average. in the first week, the fish start producing ammonia (when they eat and go to the bathroom) and a natural type of GOOD bacteria will develop and 'eat' the ammonia, turning it into nitrite. in the 2-3 week, a second type of bacteria will begin to develop and 'eat' (oxidize) the nitrite and turn it into nitrate. when your tank is cycled, the water parameters will read 0 ammonia, 0 nitrite, and 5-20ppm nitrate.

Because you're cycling with fish in the tank, you'll have to test often esp. in the first 2 weeks to monitor where ammonia and nitrite are at. anything over .05ppm of those 2 things are considered too high and toxic to fish. Nitrate isn't toxic to fish, but feeds algae, so it needs to be removed with water changes. When cycling, you shouldn't do a water change unless the ammonia or nitrite spike, essentially, if you do a water change while you're cycling and there isn't a spike, you're setting your cycle back and it could take longer to completely balance out.

From there, once the tank is cycled, You'll just have to keep up on bi-weekly water changes (about 20% on average) to keep the system balanced and ensure all the fish are doing well. Generally, they do fine as long as the water quality (the parameters) are balanced and the tank is cycled.
  • Thread Starter
  • #3
Thanks I'll consider whether my cycle has actually reset.

I'll also add that I have an air stone running and the first tank was fully cycled after several weeks before I added fish.

The fish act normal and are not gasping for air at all. Water flow is good.

I'm also using seachem flourish 2x week, 5ml

Should I leave them in the new tank or move to a hospital tank?
  • #4
pretty sure you're cycled if you're using the same filter.

as you said, before you got this new larger tank, you had poor water quality. this is probably a latent result of that. i'd suggest doing larger water changes (50-70%). and vacuuming weekly.

there's more to water changes than just removing nitrates. there's excess metals and dissolved solid, and other organic compounds that we don't/can't test for.

some times the best treatment is just doing frequent large water changes and keeping the water as clean as possible.

the flashing could be a sign of a parasite. maybe gill flukes?
  • #5
Red gills are often due to chemical irritation. Chlorine, ammonia, and liquid carbon (Excel) have all been known to cause it.

I think API Tap Water conditioner is a bit optimistic with their dosing so it's possible it didn't neutralize all the chlorine.
  • Thread Starter
  • #6
Thanks for more replies.

I wonder if it's parasites or chemical irritation. Wouldn't any remaining chlorine leave the water (it would have been about 1 week since the water change before I noticed red)? I don't know how it works though. I dose right on, or just over the directed dose for chlorine.. Our water report does not state chloramine.

I'm not sure if it's related or not but 1 female blue Rainbowfish has recently developed a slightly arched spine and within the last 24 hours I've noticed a very very slight spine bend to the side.

I'll see what the LFS says, too. Worried if I leave them in the main tank they could put parasites in the water column (if that's how it works) but also if I move them to quarantine and medicate them that I might be treating them for something they don't have and causing more problems.

Thanks for bearing with me. Any other suggestions?

Update: went to LFS and got fluke and parasite treatment (praziquantel) and will treat the tank. Will update again after the course.
  • #7
Yeah, if it's been a week since the last water change it should have resolved one way or another by then.
  • Thread Starter
  • #8
I'm nearly at the end of the second course of praziquantel.

So far the red gills are the same or slightly worse (maybe), but the guppy that was flashing appears to have stopped (also dropped a fry or 2). However, this guppy has been giving white feces... Not all the time, but when she does it's usually stringy, but once was thick.
1 of my bn catfish died as well.

All nitrogen levels are still at 0.

I did a 25% water change before redosing as per instructions.

Because parasites can be tricky to kill due to their eggs, and the fact that only 1 fish has parasite symptoms and the rest simply have red gills, what could I do? Could it be bacterial instead?

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