Fish suddenly dying off

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Larry Little

Aquarium Advice Regular
Joined
Feb 18, 2017
Messages
98
After being away from aquariums for 30+ years, I've had my 65 gallon tank set up for about 2.5 months. Strictly old school, it has natural gravel, hard limestone rocks (from around the Beaver Lake area in NW Arkansas), driftwood bought from an aquarium shop and seasoned for about 12 months, and live plants. I'm using a Bio-wheel filter and a submersible heater. I added liquid bacteria (this was new to me) and let it cycle for about a week. I began with Otocinclus (6), then about a week later added two banded Plecostomus and three Corydoras sterbae. About a week after that, I bought six small (nickel body size) silver angelfish, then a few days later added six blue rams. The rams died off to one blue and one bolivian that had been part of the ram purchase by mistake (both species were in the same tank at the store). I added a trio of marigold swordtails, then a trio of pineapple swords.Everything remained stable with the fish eagerly eating, no shyness, angels growing like weeds, etc. Then about a ten days ago, I six small black angels. They seemed to do well until I then tried to replenish the ram population a few days later Since that time, I've been experiencing a die-off. All but one of the black angels have died, three of my original silvers, and several of the rams. No apparent disease other than one by one ceasing eating, then hiding, then dying. Now all three of my remaining silvers are hiding and not eating. The rest seem to be more shy, but eating well.

Did I get too greedy with my last additions? Could this have knocked the nitrogen cycle out of whack in a tank this size? I've done a couple of partial water changes; have not tested the pH or nitrogen (as I said, old school), but I think I'm going to break down and get the kits to do so.

Obviously I'm not going to add any more fish for a while. I would be grateful for any insights, advice, or information that y'all could give me,

Thanks in advance.
 
After being away from aquariums for 30+ years, I've had my 65 gallon tank set up for about 2.5 months. Strictly old school, it has natural gravel, hard limestone rocks (from around the Beaver Lake area in NW Arkansas), driftwood bought from an aquarium shop and seasoned for about 12 months, and live plants. I'm using a Bio-wheel filter and a submersible heater. I added liquid bacteria (this was new to me) and let it cycle for about a week. I began with Otocinclus (6), then about a week later added two banded Plecostomus and three Corydoras sterbae. About a week after that, I bought six small (nickel body size) silver angelfish, then a few days later added six blue rams. The rams died off to one blue and one bolivian that had been part of the ram purchase by mistake (both species were in the same tank at the store). I added a trio of marigold swordtails, then a trio of pineapple swords.Everything remained stable with the fish eagerly eating, no shyness, angels growing like weeds, etc. Then about a ten days ago, I six small black angels. They seemed to do well until I then tried to replenish the ram population a few days later Since that time, I've been experiencing a die-off. All but one of the black angels have died, three of my original silvers, and several of the rams. No apparent disease other than one by one ceasing eating, then hiding, then dying. Now all three of my remaining silvers are hiding and not eating. The rest seem to be more shy, but eating well.

Did I get too greedy with my last additions? Could this have knocked the nitrogen cycle out of whack in a tank this size? I've done a couple of partial water changes; have not tested the pH or nitrogen (as I said, old school), but I think I'm going to break down and get the kits to do so.

Obviously I'm not going to add any more fish for a while. I would be grateful for any insights, advice, or information that y'all could give me,

Thanks in advance.
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Without knowing your water parameters it's difficult to speculate about what might have happened. Your tank was certainly heavily stocked. Had you done any filter maintenance before the die-off? Did you change your feeding regimen at all? Did you get all the fish from the same LFS? Do you have a way of checking the water temperature to ensure the heater is working properly?
 
Yes to filter maintenance; twice. Gradually added foods (three flake formulas and frozen brine shrimp/bloodworms); frozen foods twice per week. Fish have all been locally bought, but from different stores. I use a digital probe thermometer (I'm a restaurant inspector so I have an extra thermometer that reads to the tenth of a degree.
 
Yes to filter maintenance; twice. Gradually added foods (three flake formulas and frozen brine shrimp/bloodworms); frozen foods twice per week. Fish have all been locally bought, but from different stores. I use a digital probe thermometer (I'm a restaurant inspector so I have an extra thermometer that reads to the tenth of a degree.
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Understood. Yes, it's possible that your biofilter overloaded, especially if during filter maintenance you lost some of the beneficial bacteria (that could occur if you replaced or cleaned a large amount of media).

If there are no visible or behavioral signs of disease or injury on the fish, then I would recommend getting a test kit and checking the levels of the nitrogen compounds (ammonia, nitrite, and nitrate) as well as the ph of the water. If you have detectable levels of either ammonia or nitrite, that could be your fishkiller; if your nitrate level is high (>60ppm) then that could be contributing to the problem as well. The water conditioner Prime will help protect your fish from ammonia or nitrite poisoning until your nitrogen cycle is reestablished.

Since your tank is heavily stocked, more frequent water changes and substrate vacuuming might be a good idea, especially if you have high nitrate levels. Also, extra aeration (if you have the means to provide it) is helpful in a heavily stocked tank, too. A small sponge filter would not only provide some more aeration but would also give you some supplemental filtration as well.

I would avoid adding more fish until you get your baseline water parameters and can ensure that your nitrogen cycle is working. If you're at all like me and have a heavy hand with the fish food, you might try cutting back a bit at feeding time if you can while ensuring that everybody gets a bite to eat. Uneaten food in a crowded tank will also put a strain on the nitrifying bacteria.
 
Besides the angels and swords none of those belong in anything but an establioshed aquarium.
They are all sensitive to any swings or even the slightest levels of ammonia or nitrite..
Any water changes? If your filter needed maintenance certainly you have made several water changes? Most change water on a schedule derived from test or that is in excess of what is needed.Many weekly ,while some only maintain filter monthly or less.
 
That a lot of bioload. I would be surprised if there wasnt lots movement in parameters.
 
Bioload is for me very tricky. It was, even in my professional days as a keeper. The standard "quick and dirty" formula of surface area to calculate inches of fish just about worthless. For example, the calculator site I checked ended up saying I could safely house 52" of "Slender-bodied" fish of 31"of "full bodied"Their examples were of tetras and oscars, which is fine, but how do you quantify the difference in biomass between say, a neon tetra and an angelfish; both are "slender-bodied" but vastly different in their overall biomass. As of today, I have two angelfish (body size - silver dollar), one angelfish (body size - nickel), 8' worth of rams, 9' of bloodfin tetra; 10'' of swordtails, 6" of cory cats, 5" of plecostomus, 6" of otocinclus.

Have done an approximate 30% - 35% water change two weeks ago and again today; lost an angel, but now have rams guarding a nest.

The pH is around 7.5; nitrates are around 80ppm. To say I'm flummoxed would be putting it mildly.
 
Many use aquavisor. However none are perfect. Best to research each individual species you plan to keep imo.
With that load 50 percent wc probably the least youll get away with. To me it would be easier on you and fish to lessen the fish count. At 30 percent tds is rising and not enough ammonia and trates are being removed. So as time goes on gets worse.
 
Hey all -- Well, I've gone 3 days since the last death. But, Since I did my last water change on Monday, all of my fish in this tank are very skittish and shy. They all go into hiding when I go to feed, even the 3 angels; all are coming out to eat when I back off.

One interesting sidebar; two of my blue rams paired off and laid eggs.
 
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