Diseased Silver Perch

[GaryD]

Hi,

New APHQ member Mattquaponics has posted a call for help on BYAP......here

To summarise, Matt has been keeping 100 silver perch (ranging from 120mm to 300mm) in an IBC......and they have contracted at least one disease.....with the likelihood that he has more than one problem.

He now acknowledges that this was too many fish but he was following advice when he stocked the system originally. Guess where the "one fish per 10 litres of water" nonsense comes from?

Matt has sought help from other BYAP members.....and (as if he hasn't already got enough trouble on his hands) has attracted the attention of one who, having consulted the aquarium websites, has prescribed a treatment involving Potassium Permanganate.

The first thing that his "adviser" should have told him is that he's not a fish vet and that, before putting anything like potassium permanganate into his system, he should consult one.......or, at least, he should be seeking the advice of DPI fisheries staff.

What Matt's "adviser" won't have learned on the American aquarium site from which he so liberally quotes (without reference) is that, diseases like those that Matt has encountered, are notifiable.

What Matt should do is:

• Euthanise the fish in the system.....and dispose of them carefully.
• Sterilise the system thoroughly.
• Equip the system with solids removal devices. Most of Matt's problems stem from high organic loading.....too many fish/no solids removal.
• Start again.....with not more than 50 fish.
• Consult more credible information sources on silver perch like this one.

Matt, I'm sorry that this happened to you. You're not the first and, regrettably, you won't be the last. See this unfortunate episode as a lesson in not taking advice from people who don't know what they're doing.

Gary

[Pugo]

Mattquaponics
I would take Gary's advise on this one, as you really have no other choice anyway.

[Earthan Group]

Personally, I find it impossible to diagnose these types of diseases accurately by a photo though my guess is on redspot. The system description tells me little other than a high organic load. That will be the primary issue as a high organic load is responsible for most disease issues. From memory the use of Potassium Permanganate is restricted and may require a minor use permit (excluding aquariums...). If inexperience, I would avoid using it, even some of us experienced guys avoid it. While it is widely used in aquariums, these little fish farms are not aquariums so give it a miss.

Most fish that have gone that far in a disease generally do not survive and suffer a slow and miserable death. Dispatch them and nuke the system, start again. The disease path will not have been the gravel or the water, but the system and management itself. Lower the stocking density to around 10kg/m3 and visually check your fish at least once a month. That means take one or two out and look them over for issues.

[Mattquaponics]

Thanks Gary, Pugo and Ed for your interest in my situation. I have decided to destroy the fish as mentioned and start clean, while making a number of up grades to the system. I'm arranging a few extra grow beds, already have a larger fish tank and am looking at swirl filters and separate bio filters to better manage the system. Would you guys be recommending replacing all the gravel and plants as well?? How would you recommend sterilizing the whole system? (That seems like alot of boiled water to me..) Thanks again.

[Pugo]

Well, sterilizing the whole system is the best way to go, I would say drain the system completely, allow it to set in the sun for a few days, If it had happened to me I would also use a light solution on chlorine, or just fill the system with chlorine water, then run the system for a few days until the chlorine is gone. I would not use the growbeds as your bio filter. If you are going to build a simple mechanical filtration system, I would build a brush filter, bio-filter setup. A swirl filter is nice but not enough.

[MingJohan]

Mattquaponics, have a look at Pugo's system. It's small and compact and also look at his test records. I agree with Pugo, If it was me I would also used chlorine, to sterilize the system, I don't have a system yet, still researching AP. I will just test for chlorine before I start up after a couple of days to make sure that their is no Chlorine in the water. Keep the water aerated if you use chlorine.

BR

J

[Mattquaponics]

Thanks for that. Would simply adding a little pool chlorine to new fresh water for a couple of days and then draining it do? Plus drying the system out and sunning it for a couple of days. Where can I view Pugo's system? Plus are there any good sites for DIY Brush Filter systems?

[MingJohan]

Pugo's system http://www.aquaponicshq.com/forums/s...wan-Chronicles

If u ask him he will be more than willing to help .... he build his own brush filter system....

Just be sure that the HTH don't contain any harmful additives!

I'm Also reading that some people use UREA to help with the cycling of there systems.

Please don't see it as advice as I never did it nor use it. I'm only share information that I collect while researching, for my own system!!!!!

BR

J

[Joey]

Hi Matquaponics

My first batch of 60 Silver perch died in my relatively new aquaponics system when I added unwashed river gravel to a grow bed. http://www.aquaponicshq.com/forums/s...date-from-Joey
The fish had what I thought was a fungal disease however I have seen the ulcers on the fish photos you posted on BYAP and I believe my fish had similar ulcers. New fish have since been added to my system and this problem has never reappeared.
My system has since grown and so has my filtration capacity. I believe your problem was partly caused by adding unwashed river pebbles to your system clouding your water, this added to the stress on your fish. Since my initial loss I have added more river pebbles as well as drainage scoria to newly added components of my system and I always first wash them thoroughly first with town water.

Cheers

Joey

[Pugo]

Well, I do enjoy my system design, there are no siphons it is a continuous flow system. My filtration system has been a dream to deal with no headaches as all. Other than clean the brush filter out once a week. I would be happy to help you out as far as questions go.. There are also many others here with a great deal of knowledge on the subject that will chime in on any questions you may have so feel free to ask,,,