Backyard Aquaponics
A place to discuss aquaponics

Hi all,
We have been avidly reading the posts in this 'fish problem' section! We are having some similar issues to other people, though we are not losing a lot of fish. Every now and then we get one with 'goo' on it, and tatty fins and tail (also their eyes become opaque and get covered in the goo as well). We have tried formalin (as per the recommendations from the supplier) which seems to have worked previously, but currently have one large (over 1kg) SP whose dorsal fin seem to have pretty much disappeared, has a tatty tail and has this same goo (mainly white but some green mucky areas too). We don't like the idea of keeping using the formalin! Also, despite looking tatty he is pretty quick and couldn't catch him tonight. All the others look fine.

After reading lots, we are still not sure if it is ich, a fungus or a secondary infection due to stress (they were not handled well we think, and were possibly damaged physically as well as stressed). Each of the other fish that have had the same problem were also new...so could be something that was introduced or just plain poor handling.

From reading all the posts and related links we are thinking we should be adding salt to the pool, and would just like clarification/checking:

Another thread mentioned rolling the affected fish in salt then put it in a salt bath?

The general opinion seems to be 3ppt- so for us this would be 30kg salt in our 10,000 litre pool??? (Heck!!!)

Does we maintain that salt level permanently, or is it a treatment period only? In which case we could drain part of the pool before dosing with salt for a short period (so we can still aerate) then top up the pool again.

We should use pool salt or marine salt? Someone previously bought some from Bunnings, is this ok?

Someone said to use a salinity refractometer to measure the salt level, I just bought a 'salt level test kit' from Vebas, will that be ok or does it measure something different?

Sorry for the essay and 20 questions, but we want to get it right!!

BTW the pool has 10x 500-700g barra (for two months) and 4 x 1-1.5kg silver perch (for the last week), it also has floating plants not grow beds.

Many thanks
Deb and Mack

Do not roll your poor fish in salt! That would burn (think pouring salt on a wound.) I am assuming you want it to live.

However a salt bath or salt dip could be appropriate for a fish you can easily catch. Do some research to find out the appropriate concentration of salt and period of time for the kind of fish. Some species are more tender than others to salt. When dipping or bathing a fish in a salt bath, always supervise and if the fish starts floating funny, put it back into the regular concentration of water.

When ever salting for a bath or the full system, always fully dissolve the salt in buckets of the system water before adding it into the system. Chunks of salt simply thrown into the system may sit on the bottom and fish sometimes sit on the bottom and could be burned by it.

You can use plain salt (make sure you don't used Iodised salt.) Solar salt like for a water softener or pool works so long as it doesn't have any other additives. I have gotten the solar water softener salt in 18 kg bags from the grocery store for under $5 US before though I think the price has gone up lately.

Thanks TCLynx
Just been reading some more and pretty definite that they have sap- looks exactly like it. It would seem to fit with our situation too-probable damage from handling and transit, and being placed in a pool much cooler than where they have come from.

Now to just check the salt concentration requirements....

do you have any sort of "quarantine" system that you can keep new/sick fish in for a while before chucking them into the pool? Might be a good thing for treating/salting or even just getting them used to your conditions slowly before putting them into the big system. Would make salting easier as well as perhaps being small enough to heat it a bit when needed and being able to slowly adjust temperature, pH etc to make the transition easier. Always difficult transporting large fish.

you should be able to get 25kg bags of pool salt from B for about $6

Yep...look for "Sunray" brand.... pure sea salt...

Okay, got the salt, the only pool salt they had. Came home from work to one very sick looking fish on the surface but boy did it swim away quickly when I tried to net it!
Did a test on the water- pH 7.6, ammonia 0, nitrate 15, DO 4.0, nitrite 0.25 or even a bit more, which has gone up from 0.1 previously. I am presuming this is because we have started feeding the fish by soaking the pellets so they sink (previously they weren't eating at all), so now there is food left on the bottom. Barras tending to huddle together, though several did eat again tonight with the sinking method.

Am doing a partial water change to reduce the nitrite.

I thought if I can catch the fish (there is one other with the beginning of sap too) and put them in a bath of 12ppt salt, that may help.

Then do I do the whole pool at 3ppt? and does that stay like that forever??

Thanks

$5.72 for 25kg to be exact

Hmmm, $5.84 here!!!

What do you think of the plan? If I can get the darned fish!!! I have drained part of the water in the pool and now wonder if I should put the salt in now so it is a higher concentration, then add the top up afterwards to get it to 3ppt??

Also, we seem to have an aggro SP...it seems to really chase the other SP and barra, which may explain why they are huddling????

Mine cost me $8.50 for 25kg. Darn city dwellers get all the bargains.

Removing the one infected fish and salt bathing @ 12ppt would be preferable.... but if it's Sap... then there's a chance the water is contaminated anyway....

3ppt wont do any harm whatso ever... even permanently.... as Barra have high salinty tolerance... and at 3ppt... it shouldn't affect your plants....

If you haven't got a lot of plants... and can't catch the fish... then I'd go to 6ppt... probably would regardless...

I'd even consider a follow up treatment of formalin if you suspect Sap.... then dump most of the water... refill and then salt....

"it shouldn't affect your plants"

Except strawberries.

Another thread for more info:

http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=3179&hilit=salting

Thanks for the advice. Did read that thread which certainly helped, plus a link to koivet which explained about sap. This is certainly a very helpful forum!!

We only bought one bag of salt...but have drained some of the water out so will put whole lot in so it will be a bit above 3ppt. Can get some more tomorrow. Will see if the fish cooperates now so it can go in a higher concentration for a while!!

[quote="RupertofOZ"]Removing the one infected fish and salt bathing @ 12ppt would be preferable.... but if it's Sap... then there's a chance the water is contaminated anyway....

3ppt wont do any harm whatso ever... even permanently.... as Barra have high salinty tolerance... and at 3ppt... it shouldn't affect your plants....

If you haven't got a lot of plants... and can't catch the fish... then I'd go to 6ppt... probably would regardless...

I'd even consider a follow up treatment of formalin if you suspect Sap.... then dump most of the water... refill and then salt....[/quote]



Thanks so much for this clarification. Did manage to eventually catch the affected fish and put in 12ppt, then back in the pool which had managed to get to about 3ppt. Bought more salt next day and added another bag (50kg in total- boy does that take a long time to dissolve in tubs!!!). All the fish looking quite happy and the sap affected one clean and active once more.

More questions however- the pool is now looking a bit cloudy, is that because of the salt or could it be the perch stirring up the algae from the sides and bottom of the pool?

Should the pool stay at the just under 5ppt it is currently or should we drop it down to 3 now all is well??

Does a higher level of salt affect the biofiltration/bacteria in any way?

We are currently working out how to set up a quarantine tank so we can avoid some of these problems!!!

Thanks
DandM