Backyard Aquaponics
A place to discuss aquaponics

Hi there,

Sorry, I'm really new to aquaponics. I am running an aquaponics system with the fish in a cut open IBC bin with a grow bed above that filled with gravel. I set it all up about 2 months ago, gave it about a month to get settled and then introduced 5 comet goldfish. The goldfish seemed fine but they were very inactive and werent eating much and I figured it was because the water was too cold (the system is outdoors). I then put a heater in and got the water temperature up to around 15 degrees celsius, and saw immediate improvement. The fish suddenly started eating.

A couple of weeks later though, they became very dormant again and didn't eat much and then suddenly one died. I panicked a little bit and did 3 water changes of about 20% of the water on 3 consecutive days. With each water change I also added a product called aquazyme on the advice of the local fish shop. I might have overdone that a bit, I'm not exactly sure what the dangers are of putting too much of that in the water (see photos attached).




Anyway, then a few days later another fish died. I took a closer look and it seemed like there might have been some dark spots on the fish but I really dont know much about this stuff so it could have just been natural discolouration following its death or possibly even just my mind playing tricks on me. See photos.



I then tested my water and found that everything looked fine, except maybe the pH level was a bit high (seems around 8.5 - 9).



I didnt really know what to do about this so I left it and then the next day found another fish floating. This time I noticed this white sort of mucus type stuff around the floating fish's body and also saw a similar type of thing on one of the other fish in the water that was still alive but not looking well.


Does anyone know if this white stuff is an indication of what is killing my fish and whether it is related to the high pH level and what I can do about it?

I should mention that at the moment there is nothing growing in grow bed, though the water is still being pumped up into the grow bed and draining out into the fish tank. I'm not sure if that is of any relevance but just thought I should give as many details as possible.

I also fairly recently put some live plants in the water which I obtained from the local fish shop.

Any help will be greatly appreciated.

Thanks
Pall

Looks like you've got some sort of fungal or bacterial problems on the one fish. That may or may not have been the initial problem. From what you described the system may not have cycled during the first two months because the water was cold initially. If this is the case then it wouldn't surprise me if you had an ammonia or nitrite spike. On the other hand the introduction of plants from the store may have introduced a disease organism as well.

5 comets of that size in an ibc shouldnt cause ammonia problems, ive had over 80 that were full grown in a 2.5kl tank for months on end before ammonia caused deaths.

your PH could come down at 8.5 - 9.

since you are heating the water, are you measuring temps? if so, what sort of swing do you get each day?

there is a chance that raising to 15deg gave you a nitrite spike, because of rapid bacterial growth, but again, that is very few fish for the tank and goldfish are very hardy.

Yep, you're right, I wasn't paying close enough attention and was just thinking about the sequence of events .

One other thing, - it could also be a parasite and the fish could just be producing lots of slime as a response.

Bringing the pH down might help as Yavi mentioned and salting might help as well, even if it's just for stress.

Thanks.

So if it is a fungal or bacteria or parasite problem, is there anything I can do about it?

What could I do to bring the pH level down?

I have been measuring the temperature but doing it rather sporadically and everytime I check it is around 15 degrees Celsius. I haven't really made a considered effort to measure swings between morning, daytime, nighttime etc.

What is salting? Do I just add salt to the water? If yes, how much?

Cheers

yes salting is just normal salt, but not table salt - no iodine or anti caking agents. use pool salt.

salt based on PPT, so 1kg salt per 1000L of water is 1 part per thousand.

usually salting is done at about 2ppt for normal conditions.

hospital conditions are about 6ppt.

Regarding the ph:

Under advice from others on this forum, i have started treating my tapwater with hydrochloric acid (sold as muriatic acid at the local ace hardware). I treat it in a separate container, outside the system until the ph is stable.

For chlorine i am dropping in a pinch of vitamin C (ascorbic acid on amazon) and either an airstone or a pump/fountain for like a day.

Then i ph test the water until it gets down to like 6-7 and i have been adding it in gradually. I have a 22 oz beer can that i have been manually transferring the top up water into the sump a few cans at a time.

The pH adjustment shouldn't be a problem just keep at it. Keeping the system water pH changes to 0.4 pH units with each top up is a good goal so that it doesn't stress the fish. Any idea how much the adjusted top up water changes your systems pH? It doesn't sound like it's having much effect since your pH is still way up there.

You could also take a known amount of system water, say 5 gallons and add Hydrochloric acid to see how much it takes to lower the pH where you want it. By doing this you can figure out how much it would take to do the same to your system - It's a simple ratio because the amount needed is proportional to the volume of water.

A/5 gallons = B/system volume (you'd be solving for B)

B = (A x system volume)/5

Once you know this you could take the goldfish out and adjust the water. The goldfish could be slowly acclimatized to the lower pH by having them in a 5 gallon bucket and gradually adding the newly adjusted system water. It's best to have them somewhere out of the sun. This is a huge pH change so take your time and keep the goldfish water aerated as you go. I'd probably not feed the goldfish or feed very very lightly until you can get them back into the main system (their waste will cause ammonia buildup an unfiltered container).

It might be a good idea to give the fish a salt dip separate from any salt additions to the system. This is usually done at a higher concentration of salt and is a brief exposure of up to 10 minutes at a concentration of 15 ppt (I'm going from memory so there's a slight chance I have the numbers wrong but I don't think so). Watch the fish for signs of stress like rapid jerky movements or loss of equilibrium, anything that doesn't look normal. Take them out if they appear to be having troubles and put them in whatever container you're having them in while you adjust the pH of the system.

I usually shoot for 1 ppt in the system water
3 - 6 ppt is used to treat parasites and might help with other things although it's very difficult to identify some problems without a microscope and treating them may be difficult as well. It's not recommended to use antibiotics within the system because of the bacteria in the biofilter. A UV sterilizer will reduce the numbers of pathogenic organisms that are free floating/swimming and might save other fish but won't help much with a fish that's already infected. I'm not recommending you get one of these and very few systems have them.

Hope this helps.

personally if it were me i would kill any with fungus, salt to 2ppt and then buy more.

unless you have some other major stress issue (zinc / copper, temp fluctuations, overly hard / soft water) then i have found goldfish normally do ok once the sick fish are removed.

may be best to put all your fish in a temporary home, and get a second small tank/aquarium for hospitalisation treatment.... That way you can treat the fish independent of the AP and the AP independent of the fish.
The hospital tank allows for higher levels of salting and other treatments that you cannot use in the AP.

Yav has some hard advice, but may be the way to go rather than simply having the problem just move from fish to fish.
At least keep the sick guys separate to the healthier ones.

In my case in the early days when I had one tank with a hit of ich I used the opportunity to detach my fish tank and refill it from scratch with scheme water (ours is chlorine only so no residual effect) which tends to sort out the fish tank bacteria fairly well. Then couple days later (once gassed off) just rehooked the grow beds.

In your case it would give you a one off chance to get all your water issues sorted out without fish in the system.
Your water issues have (probably have) caused the fish stress which leaves them susceptible to bacteria/parasite attacks.

you are in summer so things will kick back in pretty quick and all your bacteria is still in the grow bed.
plants are fine if you leave water at the bottom of the grow beds and water/circulate daily.

good reason for having a system with multiple fish tanks.

I've had some come back from bad fungus in the past, with just salting. I wouldn't knock them on the head yet.

Keep an eye on how much food you're feeding them, mine flared up when I had too much uneaten food at the bottom of the tank, it went gross and spread to the fish.