Irridescent Sharks, Recurring Fin Rot (over and over)

[BobFish]

I've had a problem with Fin Rot over and over again lately. Tanks specs below, only two fish in the tank. One fish has lost 50% of each side of his tail and the other about 20% in the current cycle.

I treated the fish with Jungles "Fungas Clear" (two cycles of about 5 days duration) and it seemed to clear up. Change 25-33% water in between, stabliize the tank for a few weeks... looking better... but it was back again the next month. I've been though about three cycles of this treatment pattern over about six months now and they have it again, very badly this time.

I need some way to "cure" this...not sure what to try.

Tank has only two fish now - two irridescent sharks, about 6 years old. Had four, but I lost two last year in a couple months (likely related as the fin rot started around then). The fish are somewhat lethargic (sleeping much of the day and more nocturnal now) but aside from the nocturnal part that doesn't seem unusual in my experience with two mellow, older irridescents with no one around to bother them.

30H tank. Not perfect on maint by any means, probably a little slow on the water changes, but the last set of sharks lived 20 years, so I'm not all that bad at it. Tank always seemed to head acidic in days of old but for unknown reasons it's been heading heading alkaline the last year or so. I try to keep the PH around neutral to 7.0 to 6.8 as best I can... but it does seem to drift now. Nitrites measure "normal" at .25.

No changes at all to tank in feeding (except reduced for less fish). Fodd is Tetra flakes. No changes to tank or contents in years. Penguin 300 filter. , Filters changed off cycle with water changes. I tend to do 25-33% water changes when I vacuum/clean because it takes about that amount of water to vacuum all the gravel.

Ideas on what I should try? Thanks,

 

[Devilishturtles]

Have you ever tested for nitrates in your tank?

I have issues with my pictus catfish all the time, when I slack on water changes. They get kinda sick, usually get a growth or something on their fins, etc. When I change the water, they are miraculously good as new in a few days. Lower nitrates can go a long ways in fin repair if they are damaged at all.

Try doing nothing and changing your water maybe once a week for a a month or so and see if that helps.

Also, try supplementing their food with something besides standard flake every once in a while. They would loooove some frozen bloodworms or brine shrimp.

HTH

 

[BobFish]

Hmmm.... my chemistry knowledge is weak - I use a test kit that says "NH3/NH4+" and in the details says it tests for NH3 and NO2. It mentions Ammonia and "ideal nitrification". I see the numbers I posted originally were wrong, it measures to an ideal 0.0 level, not 0.25 as I originaly posted. Do I need to test for something additional?

How much water (% of tank) should I change if i do it once a week?

I will try the brine shrimp... I used to feed them that every other time but I got out of the habit years ago. I'll restart it.

Any other hints?

 

[rkilling1]

Nitrites are NO2 and Nitrates are NO3.

You 'should' have 0 NH3/NH4 and NO2 in your tank at all times. Ideally, your NO3 levels should be 30 PPM or lower.

BTW, aren't irridescent sharks just a 'little' to BIG for a 30H? How big are they now?

Irridescent sharks should only be housed in aquariums that are like 300 gallons or more. They get to be something like 40" long when fully grown. Allowing them to grow up in such a small tank, will only allow for health problems in the long run.

EDIT: What is the Normal, unaltered, pH of your tank water?

 

[Zagz]

I must agree that ID sharks get very very large and the problems most likely are a result of them being housed in a 30H. They are actually a catfish, not a direct shark. They may be suffereing from internal issues as they are being stunted in such a small tank.

Test for nitrates or take your water into the lfs to get a reading. If the nitrates are high, start out changing 25% water a week, and increase to 50% at least a week. If the nitrates are 40ppm or under then start with 50% a week. Taking fish that are acclimated to a higher nitrate and suddenly reducing that nitrate to 10-20ppm can also cause serious problems. The best nitrate is 20ppm or less. Fin rot is usually a result of water conditions rather than a condition in itself. Good luck and keep us posted on how they are doing.

 

[BobFish]

Do you really think the tank size is an issue? These guys are only about 5" long, and there are only the two of them in there. They really seem to have plenty of room at this point.

I will get a nitrate test kit and check that as I only have the nitrite kit right now.

ANSWER to PH QUESTION: If I don't treat the tank, it would be very alkaline, 7.3 or .4. Any idea what is drivign it that way? The water out of my tap is 6.4-6.6 so it isn't that.

 

[rkilling1]

Definitely check your Nitrates.

When the water comes out of your tap, if normally contains CO2. Once the CO2 has offgassed, it will raise the pH to it's normal value. Best way to check this is to let a cup full of tap water sit out for a day or two then measure the pH again. By that time, the CO2 and other gases will be offgassed and give you the correct reading.

A pH of 7.4 is no way alkaline (ok it is, by definition, alkaline). It may be a little higher then neutral, but no where near unacceptable. The pH is driven by the buffering capacity of your tank. IE KH. Having a pH of 7.4 is a good thing. I, personally, would not change it. All you are adding is probably a phosphate additive that is NOT needed.

Most people, if not all, would recommend not touching your pH unless it is WAY outside of the norm. Something like 8.8 or 5.4.

It is BETTER to have a constant pH, rather then have one that is buffered and changing. You want STEADY parameters.

As far as size goes, 5" isn't that big, but you have to understand that a fish will NOT grow to the size of the tank, no matter what the LFS or friends have told you. The inerts of the fish will be crammed together and make the fish very unheathly. That is something you will not be able to see on the outside. Having those fish at that size, I doubt it is internal at this point. Clean water is your best defense rightnow. Slowly increasing your PWC's to about 50% per week. I, personnaly, would stop changing the pH.

 

[BobFish]

Followup question: Should all the cleanings all be "full" cleanings where I use the siphon vac to get right down into the gravel, or should some of them alternate to be more of just a "standing water" change.

Also, instead of doing a (example) 25% change once a week, would it be better to do 12% twice a week - or is it better to change large amounts of water at once when trying to cure a condition like this?

 

[rkilling1]

With only doing 25% PWC, you may not be able to clean the whole substrate each time. Just do as much as you can each time. You will just have to remember where you cleaned the last time and start from there until you have cleaned all the substrate and then start all over again.

Twice a week or weekly really doesn't matter. Most people do them at one time to save on the time it takes to do them. Just remember, if you haven't routinely done PWC's, only do a small amount each time and increase the amount each time. You don't want to shock your fish with clean water.

BTW, what did the NO3's end up being?

 

[BobFish]

Nitrates are .40. Last water change was about 5 days ago, 25%.

 

[rkilling1]

Nitrates are .40. Last water change was about 5 days ago, 25%.

That's .(point)40 or 40 (forty)?

Was that after the PWC?

 

[BobFish]

Just following up... started with a 25% change as suggested and a reasonable amount of vacuuming. Nitrates came down to 30 so I went to a 50% change last time with a more serious vacumming. Fish are steadilly improving, fins are almost back to normal for both.

It's been a few days since the last change, nitrates are around 30, maybe a little less (scale is not that accurate between ranges). Should I stick with 50% changes until I get to a level 20 on the nitrates? Or drop back to 25% to reduce the stress of the change each time?