Daily fish deaths after new stock

I'm ruing my decision to give in to temptation not to quarantine new fish (a colony of checker barbs), and now I'm experiencing daily sudden fish deaths a week or so after in my big 160-gal planted aquarium. A few big clown loaches and denisoni barbs have died, and it looks like my big angelfish and a couple of old rainbowfish are gonna follow them soon too. The tank has settled very nicely for years too...

Now, regardless of what kind pathogen causing it is, I'm preparing for the worst and resigned if all my fish eventually die in the coming weeks/months. My question is, after complete fish depopulation, will the pathogens die off completely if I keep the tank fish-free, but keep the plants and snails, for say 3-4 months?

Thanks and I appreciate any feedback

 

Filling out the emergency template can help other members get more details. Don’t lose hope yet! Your fish could survive. it really depends on what disease or parasite is is.

 

I agree with Sheldon! Not too late to try some troubleshooting to save the tank. You say a few fish look like they are going to go soon . What are their symptoms? Expensive for 160gal, but if it was me I'd be throwing in a dose of Maracyn, Ich-x and Paraclense to cover a bunch of bases and try to protect the rest while I figure out what is going on. You could also fish the new fish back out into a quarantine tank to try to minimize further infection spread if they are still actively shedding whatever is ailing them.

 

What are the symptoms?

 

Alright, let me try the emergency template.

Tank
What is the water volume of the tank? Around 227 gallons (864 litres). I said 160 gallons before, that was incorrect.
How long has the tank been running? Around 6-7 years.
Does it have a filter? 100-litre sump filter
Does it have a heater? No. I live in Indonesia, so tropical climate all year round.
What is the water temperature? Around 27-31 C depending on time of day.
What is the entire stocking of this tank? (Please list all fish and inverts.)
Existing stock :
- 1 adult Angelfish
- 6 big adult Rainbowfish
- 7 adult & sub-adult Clown Loaches
- 5 adult Empire gudgeons
- 3-4 horned Nerite snails.

New stock (added about a week ago) :
- 10 Pentazona barbs
- 50 sub-adult Checker barbs
- 50 adult Checker barbs
- 7 juvenile Rainbow Shiners
- 5 juvenile Boesemani rainbowfish
- 4 Siamese Algae Eaters
- 4 sub-adult Denisoni barbs
- 15 horned Nerite snails


Maintenance
How often do you change the water? Once every 2 weeks
How much of the water do you change? 75%
What do you use to treat your water? None. I use ground water.
Do you vacuum the substrate or just the water? Just the water.

*Parameters - Very Important
Did you cycle your tank before adding fish? It's a years-old established tank, so this question is moot.
What do you use to test the water? None. Aquarium test kits are imported and insanely expensive in Indonesia, so I do big enough water changes to not worry about water parameters.
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.
Ammonia:
Nitrite:
Nitrate:
pH:

Feeding
How often do you feed your fish? 3 times a day.
How much do you feed your fish? As much as they can finish in a few minutes.
What brand of food do you feed your fish? Tetrabits, some local brands, bloodworms, dried mini shrimp, and live mealworms.
Do you feed frozen? Yes, bloodworms.
Do you feed freeze-dried foods? No.

Illness & Symptoms
How long have you had this fish?
The oldest one that died had been with me for at least 5 years. That was the angelfish.
How long ago did you first notice these symptoms?
Two days after the new stock came in.
In a few words, can you explain the symptoms?
Very quick death with no or very little symptoms. The ones with symptoms that I can see are from the rainbowfish (loss of scales, no appetite, death within a few days of symptoms showing) and the angelfish (no appetite, gill operculum seemed squashed on one side, death within one day).
Have you started any treatment for the illness?
Not yet as I don't know the nature of the disease yet.
Was your fish physically ill or injured upon purchase?
A few of the new 50 sub-adult checker barbs had ich. Upon observation in a big floating net inside the main aquarum, 50% died within 48 hours, so I discarded the whole lot and ordered another 50, which looked much much healthier and are already adults.
How has its behavior and appearance changed, if at all?
I will explain more below.

Explain your emergency situation in detail.
As explained above, I have an established 200+ gallon tank with healthy, long-time residents. The stocking is a bit sparse, and I haven't had new fish for about a year, so about a week ago I had a brainwave and decided to add a big school of small fish (hence the order of barbs and shiners) and I also decided to add some algae-fighting corps (the SAE and nerites) and some juvie rainbows to grow up and accompany the existing adult rainbows.
Most of the fish I ordered online from several stores, and most came within a 48-hour period. - - The first ones who came were the Pentazona barbs, and they looked great and perky so I added them in (acclimatised) that same day. I know I should have quarantined all new fish (as I mostly do in the past) but I don't have the space and equipment, and that's most probably my downfall.
- So after the Pentazonas, came the Shiners and the 50-strong juvie Checker barbs. The Shiners came from a breeder, so they were looking great and I added them in much like the Pentazonas. The juvie Checkers on the other hand, were tiny, and a couple had ich on them. I was afraid my big rainbows and my angelfish would snack on them, so stupidly I decided to "quarantine" them in the main tank to grow them up a bit before releasing in the main tank proper.
- The next morning, the Checker barbs had a few deaths. No big deal, I thought, they're small anyway and had a long transport, so some deaths is expected. By evening, about a dozen more died, and a couple more developed ich. Meanwhile, the juvie Boesemanis and the SAE's came, all looking great and active, so I added them in the main tank.
- The morning after, another dozen or so of the Checkers died during the night. By noon, more died, decimating the numbers to half the original. I decided I would cut my losses and dump all the remaining Checkers in the bin. This day was also the first time I noticed one of the Pentazonas died.
- Next day, one of my smaller Clown loaches died. No visible outer trauma or wasting can be seen. I also decided to order another 50 Checkers from a more reputable online store.
- Next day (which is now about three days ago), I went to an LFS to purchase some Nerite snails and a few Denisoni barbs. More Pentazonas went missing, and another Clown loach went missing. The 50 new Checkers came and looking fabulous, so I dumped them in.
- The next day, more deaths. I've now lost about 5 Pentazonas, 3 Shiners, 1 SAE, 2 Clowns, and a couple of the new Checkers. The small ones just seemingly dropped dead within half a day or so without symptoms. One of my adult rainbows was not showing any appetite and losing scales in a vertical band on her side.
- Yesterday morning, I found one of my big Clowns dead. No visible outward trauma. The ill adult rainbow also died later in the day. My lone angelfish also looked listless, breathing heavily, and has no appetite whatsoever, but interestingly its colour (especially the black vertical bands) was very intense, as if it was spawning. Also I noticed one side of its gill operculum looked somewhat caved in. Some more Checkers and a couple more Shiners died.
- This morning, the angelfish died (attached picture) along with a couple of Checkers, one of the two last Shiners, and a juvie rainbow. It's evening now as I'm writing and no more deaths occurred as far as I can observe. The Empire Gudgeons seem unaffected (so far), but I've lost about 1/4 of my old fish stock prior to the new arrivals. Of the 50 adult Checkers that I purchased, I think I have 40-ish left.
Update : One of the smaller Denisonis now showing popeye and rapid breathing.

 

Hm. Sorry to hear about the death of your fish, it's very unfortunate.

You said that you hadn't added new stock in for a while, correct? My best guess is that your tanks bioload has been overwhelmed by all of those new fish added, causing your cycle to crash and your tank is now going through a mini cycle. A tank only produces as much bacteria as waste being created, and a huge amount of fish being added/dying almost defiently caused an ammonia spike. It's also possibly that one of those fish contracted a fast moving disease that doesn't always show symptoms ( like columnaris) and that's now jumping around from fish to fish as well, although I suspect the first is more likely the case and your fish are dying from the parameters spiking. The ich could've easily been caused by this, and a medication like the others listed would help.

50%-65% will be needed to be done daily for a while to bring those levels down. If test kits are too expensive where you are, most stores will test for free.

 

Update : one of the smaller Denisonis now showing popeye and rapid breathing.
Thank you for the reply. At first glance the number of new fish might sound a lot, however waste-producing wise and mass-wise, a single big rainbowfish or a big adult clown loach is equivalent to about 30-40 of the small fish.
My rainbows and clowns are about 6 inches long and bulky, while the new small fishes are only 0.5-1.25 inches long and lean. So in reality, despite the seemingly overwhelming number of fish I added, the added bio-load of the new fishes is probably equivalent to adding 3-4 adult rainbows or clowns to a planted, well-established tank with an oversized sump filter.

 

I agree with cdwag29
The sudden large addition of fish likely caused an ammonia spike.
Already stressed new arrivals wouldn't have much resistance to unstable water parameters.

 

The rapid breathing could easily be a result of ammonia poising, and a lot of times fish will start gasping for air as I believe it can burn their gils (correct me if I'm wrong.) Popeye is also linked to poor water quality.

A large water change is needed asap.

Update : one of the smaller Denisonis now showing popeye and rapid breathing.
Thank you for the reply. At first glance the number of new fish might sound a lot, however waste-producing wise and mass-wise, a single big rainbowfish or a big adult clown loach is equivalent to about 30-40 of the small fish.
My rainbows and clowns are about 6 inches long and bulky, while the new small fishes are only 0.5-1.25 inches long and lean. So in reality, despite the seemingly overwhelming number of fish I added, the added bio-load of the new fishes is probably equivalent to adding 3-4 adult rainbows or clowns to a planted, well-established tank with an oversized sump filter.

You'd be surprised. Guppies are quite small but in reality they produce a huge amount of waste. Pea puffers are even smaller and even more messy. Even though they may not produce a large amount of waste, all those fish at once can still overwhelm your tank, especially if a lot of fish are dying, and the symptoms your fish are showing are all things that are commonly caused by poor water quality and stress.

 

Agree with above. Ramp up the water changes to daily or every other day for a few weeks. It will only help, even if it is not ammonia. If you see your water getting a little cloudy that's another sign your bacteria was overloaded, so it has bloomed to catch up. That cloudiness will clear up on it's own too.

 

Hi, welcome to fishlore
I agree with the others. Really important to have a test kit. You mentioned they were “insanely” expensive (not sure what that means) but your tank and all those fish must be expensive too so it’s important to know the parameters of your tank. With the rapid deaths I would guess ammonia poisoning.

Also, now that ich is in your tank it is important to treat the whole tank for two weeks with medicine for ich.

 

Way to many new fish added!! Your bacteria just can’t keep up. You need to space out the time between adding new fish. Your bacteria needs to build up to handle the new fish. Also a 100l or 25g sump is way to small for that tank. It worked for the small amount of fish but for what your adding you’ll need much more filtration.

 

About my sump, sorry I mis-typed the volume. The sump size is actually 120 cm x 50 cm x 40 cm (filled to 30 cm water height), so actual volume is 180 litres or 50 gallons. It's an established tank, with a LOT of water volume so there's a lot of leeway/buffer for any water quality issues and for any ammonia/nitrite poisoning it should take a long time with visible stress, not just a couple of days then fish started dropping dead left and right.

Last time I added new stock before last week, as I said, was about a year ago, which was the 7 Clown Loaches each 3-5 inches long. We all know how much waste clown loaches make, and their sizes meant I effectively added about 50% more bio-load into my tank in one go. No fish died or showed any negative symptoms.

For now, the fish deaths have slowed down and today I actually had no deaths, big fish or small fish. So, I'm hopeful whatever causing the mortality are suppressed enough to not cause any more problems. In the future I'll be sure to set up a quarantine tank and medicate to prevent this from happening again. Thank you for your help.