Backyard Aquaponics
A place to discuss aquaponics

I'm determined to not repeat mistakes from last year, like adding new fish to a healthy existing system and then finding out the new fish had columnaris infection. So with that being said, I'm planning on purchasing about 50-75 channel catfish fingerlings, about 2", and would like to keep them in a quarantine tank for about a month or so.

What size tank do I need for this many fish at this size?

Also, how long really should new fish be kept in quarantine?

Should I salt the quarantine tank heavily and only keep the fish in for a day or two?

One option I'm considering is a pair of 40-gallon glass aquarium tanks that I used last year for breeding guppies, they were plumbed into a grow bed with a wetted volume of about 40 gallons of lava rock. That whole mini system has been offline for 8 months and would need some refurbishing. When it was running last year, there were about 100 guppies between the two tanks and guppies were healthy.

Thoughts?

How long they stay in quarantine depends on what you hope to prevent. I think a couple of weeks is enough for most diseases to show but it probably depends on the water temperature too. You might have to hold them longer if there is a problem. The filtration is going to be more important than the tank size but the ones you've mentioned should work if the filtration is adequate, if it isn't, you'll have to do frequent water changes.

I'm not sure about the salt levels for channel catfish . I'd at least salt it to 1 ppt for stress and slime coat building but that won't do much for killing parasites like Ich. You could try using a dip with high salt levels before putting them into quarantine or you could do the high salt levels in the tank itself.

copied here from post just made on another thread, as relevant to topic and adds to what Scotty says above.
(and would be nice to see a thread develop with useful information on the Quarantine topic)

Many food type fish are sensitive to pH differences - and even small differences can cause a 'shock'
Fish that are stressed are affected worse. In an advanced system this can result in a whole crop of fish being wiped out and take some time to recover from.


New fish should never be added directly to an AP system.
Fish from hatchery's and multiple storage etc can be carrying diseases or parasites.

the recommended procedure is to go through a quarantine and water transition phase.
have a separate tub or tank of sufficient volume for fish to survive for a week or so.
that water needs to be prepared to be as close to pH of the *original* system/transportwater of the fish.
This water should be salted to 2-3ppt (2-3kg per 1000L, 1-1.5kg per 500L etc) and have air.
The new fish should be gently added to this tank (quarantine tank) and left to recover from transport stress for at least 48 hours - keeping an eye out for any signs of sick fish or things such as ich.

at this time if you have a system with different water parameters you slowly start removing quarantine tank water and replacing it with fish tank water at 5-10% volume until such time as the fish are basically swimming in system water. This step is particularly important if you run high or low pH or have higher levels of any minerals/nutrients etc in your system.

for food fish you should keep you system salted to around 1ppt.

obviously this process is not required for things like goldfish, but are procedures common to aquaculture fish raising.

The quarantine tank can also act as a hospital tank if you later have a sick fish.
It can be moved there and treated with higher salt levels than those in the main system.


[edit] couple other things...
1. when transferring fish between tanks etc water temperatures should be similar.
2. reduce feed for fish in quarantine (often wont eat much anyway)

I quarantine my catfish in 3-4ppt salt. I prefer a mix of NaCl and KCl but for quarantine it doesn't really matter. You want the chlorides. Do NOT use Epsom salt for quarantine or nitrite protection.

I keep them in Q tank for at least 10 days and feed as filtration will allow, watching ammonia and nitrite closely. The chloride will protect fish from nitrite, but toxic ammonia is still a concern. If the temp is below 70°F or salt is less than 3ppt I would hold them longer than 10 days.

I like an aquarium Q tank because I can control the water carefully. I always like to have pH within 0.5 of the source water, and if possible temp within a few degrees. To introduce the fish I add an airstone in with the fish and use air tubing or small plastic tubing with a valve to slowly trickle QT water into the fish bag/bucket over 30 - 45 minutes. I hope to double or triple the water volume the fish arrive in, this will equalize pH, hardness and temp. I NEVER empty the source water into the QT, rather ALWAYS net the fish out and transfer them. This will minimize transferring any nasty pathogens, parasites or fungus, etc. as well as any antibiotics or chemical treatments.

In one case I shortcut the Q process and had major ich in my AP system affecting with many more and much larger fish. I had to take several 30 gal buckets and string them together with PVC piping system splitting up the fish between the buckets. I heated the water to over 85° and salted to 5ppt for 10 days. The catfish fared well and the ich was gone. Ich needs a host, so the absence of fish in the AP system eliminated it from there. It takes about 3 days with temps over 75°F.

Anyway, then to transfer the fish from QT to the AP system, I can change the QT pH and temp over the last few days to match the AP system and follow the same transfer method. DO NOT put any QT water into the AP system.

I think the introduction of an intermediate tank between original source and Q tank is important. The fish are then netted into the Q tank and the old water discarded.
You can’t switch bio filters on and off. So in my own system the Q tank bio filters are kept ticking over by being incorporated in to the main system when not in Q mode. I have also added a UV light into the Q tank loop. Switched off when not in Q mode.
By chance, my own tank is black but I note that most of the Koi people use blue tanks for quarantine. Any thoughts on tank colour to enhance identification of problems?

Titus, I do the same thing - I have one IBC growbed that I can isolate from the main system. It has a 50 gal sump tank available when needed. I think lighter tank color is helpful to see the fish and any indications of infection rather than black. I can use either an IBC for quarantine (larger fish) or a 55 gal aquarium. I put a light colored backing in the aquarium because it's hard to see the fish otherwise (black acrylic back).