Losing fish, advice appreciated

[BAW]

I have a 400l/95g community tank. I took great care in the set up, spending a great deal more on filtration and media than on the tank. I have an Aquael Ultramax 2000 filled with 7Kg Biohome Ultra and 12 chunks of EXXODUS Phosphyx, preceded by a booster filter for mechanical filtration. It took some months, but the tank consistently tests at 5ppm nitrate or under, 0 nitrite or ammonia, and phosphates 0.25ppm. I live in Edinburgh, and the water is soft. Routine monitoring and adjustment is required to maintain KH 5, GH 7.

I have three Pearl Gourami - 2M, 1F. The males are reaching full splendour, and at the moment the only aggression between them appears to be courtship, playfulness, or mild warnings.
I have 3 full grown Emerald Brochis, 4 Schultzei cory (quite young), 6 Sterbai cory, 4 Elegant cory, and, as of this morning, only 2 Pepper cory. I also have a dozen Cardinals, a Clown Plec, 4 Siamese Flying Fox, and 4 Neon Dwarf Rainbowfish.

The water is practically self-maintaining, although I do clean out regularly, and remineralise the water. I have caves set up on both sides of the tank, hiding places aplenty, mopani covered in anubias of different kinds, bogwood, and a red-leaved plant whose name escapes me but is really prospering.

A few weeks ago, I started finding dead fish. At first, a couple of Cardinals, which looked like they had been damaged, then a few days later a pepper cory and an elegant cory. I found the largest of the Cardinals stuck in a plant, stomach ripped out. throughout the process I have been looking for signs of disease, and treated with Melafix at first. I then tried Interpet's Disease away, which was recommended as an allrounder which wouldn't upset the balance very much.

After some time, one of the Cardinals seemed to have a white growth on its mouth. I couldn't tell if it was cottonmouth, or an injury, but I treated with Interpet Anti-bacteria. The following morning, one of the Flying Foxes was lying dead on the substrate, and I'm assuming it was a recent death, because it was 100% intact. It looked healthy.

This morning, a pepper cory and a Sterbai were dead, stuck in the plant near the surface, with several fleshy parts removed. The Sterbai had no head.

Am I missing an obvious predator amongst my stock? As far as I can tell, the aggression on the Gouramis' part is usually male to male, and also while breeding.

Any advice would be appreciated!

Thanks.

 

[ClownLurch]

Is anyone biting anyone else? I’ve no other suggestions and it sounds like you’re more knowledgeable in fishkeeping than me even if I did. Best of luck.

I had a mass die off last year and I know what you’re going through. Due I believe to a perfect storm of trouble:
1/ Male guppy sexual frustration/aggression instigated biting.
2/ Bad bacteria from sand stirred up by forgetting to point python into a bowl when refilling tank. Tank was very very cloudy.
3/ Possibly not washing shop anti covid gel from hands before water change.

Try removing a male gourami?

Once again best of luck.

 

[AquaBarb]

If the problem is indeed something attacking your other fish my money would be on the Siamese Flying Fox's going from your stocking. These can become very territorial and aggressive.

Cant see it being the pearls. They only tend to bicker between each other.

Id keep a close eye on the tank and watch how your fish are behaving with each other over the next couple of days and it wouldnt hurt just to do a few water changes just to dilute any possible nasties lying about.

Hope this problem ends for you soon

 

[AquaBarb]

Did you add anything to the tank just before you started losing fish?

 

[Deleted member 149562]

Firstly you need to stop using Melafix.

It will suffocate the Gourami who are surface air breathers and Melafix is unrefined tea tree oil which knackers the labrynth organs in all surface air breathing fish. Throw the Melafix and anything else with "fix" in the name away.

Going for the medications before the basics of upping your water changes is a mistake that many tend to make. Never advised to reach for the medications before increasing your weekly maintenance of water change percentages and frequency as the medications are far more liable to cause harm than actually do any good when no specific diagnoses has been made/confirmed

 

[otterblue]

If you have a sick fish to treat, I would put it in a separate quarrantine tank and add any necessary medications there - rather than adding medication to the whole community tank.

 

[FishHobby99]

If you have a sick fish to treat, I would put it in a separate quarrantine tank and add any necessary medications there - rather than adding medication to the whole community tank.

That’s exactly what I would do.

 

[Wills]

I'm not sure this is a predation issue, feels more likely you are coming across fish that have been scavenged and died of other causes.

Just from your overview a few things I'm wondering about. You mentioned that you remineralise your water? Are you using RO water or are you adding something to your tap water? I'm wondering if you have some kind of hardness swing?

As a few other people have mentioned too - did you add anything new to the tank in the two weeks prior to the first deaths?

Lastly did you notice a white patch between the dorsal fin and the tail on any of the fish?

Wills

 

[Deleted member 149562]

What exactly is your maintenance routine for this aquarium?

Frequency/percentage on water changes?

Frequency of substrate vac/plant trimming/dead heading?

Method of cleaning filtration & media and frequency?

You mentioned that the aquarium is pretty much self-maintaining but I can't help but wonder about your maintenance schedule....testing is not entirely essential unless you start losing fish for no obvious reasons

What prompted you to reach for the medications rather than increase the frequency of water changes?

Your Gourami mix is off too.....ideally the ratio would be 2 female to 1 male, not the other way around as you have it as that heightens aggression - two males effectively fighting for one female

If you can also post a full width photo of the aquarium and perhaps photo's of the affected fish....if you can remove the affected fish to a QT then ideally that would be good, treating the entire aquarium for "something" that is not firmly diagnosed is always extremely risky, as I already mentioned with the Melafix above.

The munching of fish is inevitable when you have SFF and Pleco since both will happily tuck into a dead fish if it happens to be there..... (snails and shrimps, if you had those too, behave in the same way, they are opportunist eaters) So mutilated dead fish is not a surprise given that you have nocturnal munchers in the aquarium stock.

 

[BAW]

Thank you for the answers, everyone. I will leave Melafix out of it (it was a recommendation I shouldn't have listened to.)

I know the gourami ratio skewed. I started off with four, but had to return a female which was rejected by the others. At that point I thought I had 2M, 1F, but then one of the 'females' started to change colour. I fully expect to have to remove one of the males at some point, but would like a pair from what's there.

I use Aquadur to remineralise the water—the Malawi version, which raises KH more than GH. I introduce it very slowly, in order to harden the water without risking any pH shock.

The biofiltration is running a full Nitrogen cycle now; the only reason I was testing is to verify that this cycle is completely established, as it has only completely stabilised over the last couple of months. It took a lot of perseverance to get to this stage, and I've spent a great deal more money on the filter and its contents than I did on the tank, because I was determined to establish a natural waste cycle. The mechanical filtration is taken care of by the pre-filters—the 2.3L booster filter, and the one that comes installed in the Ultramax 2000. I clean these in a bucket of siphoned tank water, whenever I notice a reduction in the flow.

I have an electric hoover thing that I regularly use to disturb the substrate and dispense with gunge, but the water consistently tests as having ideal parameters, provided I adjust the KH, so I only replace the amount I siphon when cleaning, etc. At times over the past while, partial water changes seemed logical, and I have performed a few, but this has never helped. My tap water is very soft, and I don't like having to tinker with the KH/GH all the time.

I'm not sure this is a predation issue, feels more likely you are coming across fish that have been scavenged and died of other causes.

Just from your overview a few things I'm wondering about. You mentioned that you remineralise your water? Are you using RO water or are you adding something to your tap water? I'm wondering if you have some kind of hardness swing?

As a few other people have mentioned too - did you add anything new to the tank in the two weeks prior to the first deaths?

Lastly did you notice a white patch between the dorsal fin and the tail on any of the fish?

Wills

The first thing that happened in this debacle was we lost a pair of Rams in quick succession. I can't think of anything I added that would coincide. When the water tests as it does, I'm inclined to suspect infection. I was advised—by a very reliable source—to give the Interpet Disease Away a go because it is relatively mild and broad spectrum.

However, I have noticed a small white patch on two of the Corys—on the forehead of an Elegant Cory, who's still around, and possibly near the dorsal fin of a Schultzei Cory (I can't get a look, because he's always away playing in the bubbles). The Schultzei are losing their juvenile colours at the moment, so I wasn't sure if it was related.

Why do you ask?

 

[Wills]

Hi thanks for all this information really interesting to hear your journey. Unfortunately from what you have said I think someone is advising an over complicated process in order to sell things to you. For example if you have been replacing your bio media at all everytime you do this you will end up back at square one.

Your biological process shouldnt need to take months and combnations of expensive stuff - you can do it with pretty basic equipment like a sponge filter and air pump. Can I ask what kind of test kit you are using too?

I have a suspicion that your problems are coming from you hardening your water - apart from your dwarf neon rainbows and to a less extent your Pearl Gourami you are keeping soft water species. You are better off keeping them at the same level rather than adding things to raise it as it will keep fluctuating which can stress fish and cause death. Do you know the ph and hardness of your tap water? Your Gh and Kh numbers or a ppm reading would be really useful.

Fluctuating hardness is also going to give disease (even mild ones) a good chance to get in too. I mentioned about the white patches on the back as this is a symptom of a disease called Columnaris which is often a culprit of seemingly random or symptomless deaths.

Wills

 

[BAW]

Hi thanks for all this information really interesting to hear your journey. Unfortunately from what you have said I think someone is advising an over complicated process in order to sell things to you. For example if you have been replacing your bio media at all everytime you do this you will end up back at square one.

I'm sorry, I think you've misunderstood me, Wills. The only media I ever replace are saturated mechanical media. I have had the same 7 Kg biomedia since set-up, which is designed to propagate aerobic and anaerobic bacteria. It takes several months for the denitrifying, anaerobic bacteria to develop into a full culture, capable of consuming the nitrates produced by the aerobic bacteria. They did start to reduce nitrates within weeks, but not down to the 5ppm marker I aim for.

When people speak of cycling a tank and the end product being nitrates, that's just the aerobic part of the cycle. The end result of my cycle is nitrogen gas.

I have the API master kit and API KH/GH kit, but I use the Salifert nitrate kit because the API test results are too difficult to read—same with the phosphate test.

My KH is 5, GH 7. My tap water has KH less than 3.

I have considered columnaris, but as far as I understand it this is an ever-present bacteria which finds a way in through stressed nervous systems. I'd love to isolate the stressor.

 

[Naughts]

Routine monitoring and adjustment is required to maintain KH 5, GH 7.

What would they be without adjustment? Why do you adjust the water?

 

[BAW]

What would they be without adjustment? Why do you adjust the water?

The KH dropped to 2 when I hadn't monitored it for a while. That was what alerted me to the issue. In fact, the solution almost changed colour at the first drop; just on the cusp.

 

[Wills]

I'm sorry, I think you've misunderstood me, Wills. The only media I ever replace are saturated mechanical media. I have had the same 7 Kg biomedia since set-up, which is designed to propagate aerobic and anaerobic bacteria. It takes several months for the denitrifying, anaerobic bacteria to develop into a full culture, capable of consuming the nitrates produced by the aerobic bacteria. They did start to reduce nitrates within weeks, but not down to the 5ppm marker I aim for.

When people speak of cycling a tank and the end product being nitrates, that's just the aerobic part of the cycle. The end result of my cycle is nitrogen gas.

I have the API master kit and API KH/GH kit, but I use the Salifert nitrate kit because the API test results are too difficult to read—same with the phosphate test.

My KH is 5, GH 7. My tap water has KH less than 3.

I have considered columnaris, but as far as I understand it this is an ever-present bacteria which finds a way in through stressed nervous systems. I'd love to isolate the stressor.

Are you experiencing the drop in nitrates in the tank through the media you are using? I'm familiar with the technique (I have Seachem Matrix trying to achieve the same result) but its often a bit of a mixed bag in terms of if its going to happen or not. It may come down to you having soft water but I'm not sure. I think its just hard to get aerobic and anaerobic bacteria growing so close to each other, some people here have done trickle filters or sand bed filters to achieve this separate to their main filtration with anaerobic filtration. But you are correct I thought from your post that you were changing the bio media rather than the mechanical sponges, flosses etc so thats good to clarify

Also good to clear up using the liquid tests, I was asking as some people use the strips which are less acurate so sometimes when they retest with liquid kits they get an ammonia or nitrite reading that didnt show on the strips.

In terms of your hardness, does your Gh stay consistently at 7 from the tap and does this drop in the tank through the week? Do you notice if your ph has droped by the time you get to a water change?

If it is a disease and you are noticing no other syptoms Columnaris could be likely I experienced it a number of years ago on a mature tank and it was heart breaking. I lost some big adult fish in quick succsession but eventually some Geophagus I had showed the white 'saddle' as its known and while I couldnt save any fish that showed the marks either on the mouth or saddle I did save the fish that were nonsymptomatic and they went on to live for many years longer.

Wills