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Hi all. I am a bit confused about the recent behavior of my fish. I have recently come to the conclusion that my hybrid bluegill have an external bacterial infection. From reading on this forum, it has been my understanding that a major factor leading to the infection, especially with bluegill, is stress of some sort. I won't deny that my little guys have suffered a bit of stress. In addition, I was also under the impression that sick fish, let alone stressed fish would not be interested in eating. My incredibly sick fish have been ravenous ever since the day I got them. As soon as I determined they were sick, I pretty much stopped feeding them. Two days ago I salted the FT to 5ppt. I expected they would want to eat even less, but it has not stopped them at all. They all come to the surface whenever I open the tank. They come after my finger if I dip it in (one even nailed my finger!). They continually scrounge the FT for food. When I toss in a grub from the flower beds, or a couple worms to see how interested they are, they nail it and the food disappears before it drops an inch under water.

Should I continue to feed the fish, even though they are in terrible danger of this infection?

My plants have not YET died due to the salt, but I am prepared for the possibility the plants may all drop over. If my plants did salt up and die, I would have no way to filter out the rising nitrites, further stressing the feeding fish.

I am confused about why these sick, supposedly stressed fish seem to be still incredibly hungry.

Thanks for your valuable input!


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Replies to This Discussion

Well, as they say, starve a cold but feed a fever! :)

I have tilapia, but sick fish are pretty much sick fish. Personally, I'd keep feeding them but I'd be cautious about over feeding. They may have an infection, but they aren't stressed to the point of not eating.That's a good sign! Also, it's good if their not clamping their fins close to their bodies, and if they're swimming around a lot. All good signs.

A low dose of salt is a good way to reduce stress and benefits their slime coat. Some salt shouldn't harm the plants much, but high doses can hurt both plants and bacteria, so just monitor the water and plants visually. You can always do water changes to control spikes in ammonia, nitrites, etc. 

What is the infection they have? Is it bacterial or a parasite?

I believe it is bacterial.

What do your water tests say?  If your ammonia and nitrite are low or 0 and the fish are hungry and you don't have uneaten feed building up anywhere then I'd say feed them as much as they want to eat in 5-15 minutes.  Keep a close eye on ammonia and nitrite and only feed if those are low or 0.

Small bluegill and tilapia can both be very aggressive to food.  The small bluegill in one of my tanks would come up and nibble my fingers and try to attack as I check the temperature.

Just try to keep the water quality as good as possible and hopefully the salt helps them recover.

The ammonia has been 0 or one shade above 0. The nitrites are almost always 0, occasionally a half shade over 0. Water temperatures have been fairly consistent once I insulated the tank. Nitrate levels usually around 60-80ppm.
My fish went another almost week without food (mostly). I started feeding about a day after Sheri posted her reply,in part due to her response, also because for two days in a row I found a dead fingerling with no visual signs of infection, something every previous dead fish had exhibited. I was worried these little guys had been starved.
Yesterday was the first day I did not find ANY dead fish since the carnage began. Out of 60-70 hybrid BG, I am down to 15 or so fish. We were gone most of the day today, so I didn't get a chance to check for the dead before dark, but shortly I will go out and check by flashlight. (I think that spooks some of them.)
The only stat I've really struggled with is PH. My water is most usually 8.3. I haven't been too worried, my ammonia has been very low, and I assumed the fish waste would drive the PH down. My plants are (were) growing, but I can't help but think they would grow so much better with lower PH, sooner rather than later. Meanwhile, I think the salt is finally starting to take a toll on my plants. TC, Sheri, how long should I wait before beginning water change outs to begin removing salt? How will I know when the salt is completely gone? I am thinking of putting together some sort of tank for top-off water, off-gassing, and lowering PH. Do you have a recommendation on how low I should drive the PH of the stabilized top-off water?
Thanks for your inputs! Here are a couple pictures of the most common afflictions my fish have.


I'd not worry too much about getting the salt level changed back down to 0, Just lower it enough that the plants won't be too unhappy.  Somewhere between 1-3 ppt is usually good for most veggies.  If you actually want to measure the salt level you need a hydrometer that can measure salinity in the 1-10 ppt range which is kinda hard to find.

If you happen to have a hydroponics TDS or EC or Conductivity meter you can use or borrow, you can use that to kinda estimate when you have changed out enough to reduce the salts to tolerable levels for most any plants.

I would recommend collecting rain water if possible.  Constant use of acid to adjust pH is not necessarily a good thing.  If you are going to use phosphoric acid or hydrochloric acid to adjust your top up water I would recommend getting some extra test kits to make sure you are not getting your system chemistry too far off.  A phosphorus test if using phosphoric acid and a chloride test if using hydrochloric acid.  You might also want a carbonate hardness test because it is possible to remove all the hardness of your water and leave your system prone to extreme and fast pH drops.  To run with a pH in the mid 6 range you need your carbonate hardness to be low but you don't want it to be 0, 20-40 ppm is probably appropriate but you have to test your pH daily if you are running down in those ranges and don't have long term experience on how your system will react.

Thanks for the suggestions. I am frustrated I am coming to these challenges, I have plans to end up much bigger to supply food for my community. If I struggle with water quality this much at a small level, how will I be able to maintain thousands of gallons in tanks that would need to be topped off? I will do some searching as well, but do you know of any tests reporting how much atmospheric contaminates are introduced with rainwater?
Thank you for the advice, I really appreciate all the help. REALLY.

Mark, don't give up! Larger systems are actually easier to maintain than smaller ones. A larger system will self-adjust the PH more readily.

I concur wtih TCLynx, don't worry about the salt too much other than keeping it at a level that pleases the plants. If you think it's too high, you can do a 25% water change without hurting anything. A prep tank is a good idea. You can use it to dechlorinate and to reduce the PH. Use Muriatic acid...start with a couple oz/55 gal and adjust until you have a good reading.

Your one fish looks like others have been eating at its tail. The other fish looks like it has a fungus, but I could be wrong. They both look pretty sad. With only 15 fish left, you might consider moving them to another tank (a 55 gal drum or something) and treating them away from your plants.

I have to run a bunch of errands this morning, but I'll come back later. In the meantime, others might have some good ideas.

A new system and being new to keeping fish and doing aquaponics and learning what your water will tend to do shouldn't get you too down about being able to go larger, please be patient.  Wait till you have been running your system for a few seasons before you make too many decisions about what you should do in the future.

While a larger system does tend to be more stable than a small system, going really large, as in commercial, can be a whole different ballgame and before you go "buying the farm" you really need to get some professional lab analysis done on your intended source water and study up a bit on the water chemistry as it pertains to fish and hydroponics so that you are not flailing about in the dark or asking questions on a forum when the results could have drastic effects on the operation's bottom line.

If you don't trust rain water due to pollution then you will likely need to deal with the costs of running RO filtration on the well water and then using the appropriate things to keep the pH and carbonates in the appropriate range for commercial growing.

Sheri, I don't think the fish have been eating on each other. Granted, I cannot watch them ALL the time, but I have spent a considerable amount of time observing their behavior. I have witnessed the tail "nastiness" across all the sizes of fish I have, at various stages of severity. It has been my conclusion for some time that the tail issue is health related. Even as hungry as they were, even between the largest size differences, I never saw an act of aggression against another bg. My one pike bait feeder fish, that one is different. They chase him around, but have never snacked upon him. He's probably feeling much better now that his "aggressors" have dwindled. Also, I have no need for a dechlorinator as I have a well. A new well, as a matter of fact. I live out in the sticks. But the well PH is high. I had planned on using a barrel of well water conditioned with some sort of acid for top off water (I had recently been using PH Down), but TCLynx made some excellent points about that topic.

TCLynx, I have aspirations of building a greenhouse, but am a long ways off from that. I have started with this single outdoor IBC system, and planned to move indoors to custom built grow beds and fish tanks by winter. My garage addition remodeled will serve as my intermediate "greenhouse" where I hope to raise enough for family, friends, and neighbors. Perhaps if I overcome my struggles I will even end up with enough to start selling at the local farm markets. Fear not, I do not plan on diving headlong into the commercial business without working my way up to it.
I will check around about having the water professionally analyzed. Who even does something like that? I never would have guessed I'd struggle with THIS part of the system, thought I was home-free with the well.

Again, thanks for all the comments and suggestions!

I took my water samples to as they happen to be local to me.

Now if you are just doing backyard it may not be as big a deal.

Instead of using acid all the time to adjust hard well water.  If you can collect some good clean rain water off an appropriate fish safe surface, rain water will be a lower pH naturally.


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