High Mortality Tank

[Fox46]

I have two tanks, one is 132l, the other 166, and I've been fishkeeping for just about 3 years - so no expert. In my 166l tank I've noticed the mortality rate is drastically higher than in the smaller one. It's not been a drastic sudden loss, it's just that fish in that tank, while not generally displaying any overt signs of disease, have never seemed to achieve their expected life span. For instance, of 9 dwarf rainbows acquired in October 2020, only one remains. I've lost around 8 guppies over this period, and now am in the underoing a more dramatic attrition where I had a group of 9 Platys, acquired in February this year and am now down to 4 (2 deaths this month and a third looking decidedy dodgy.) I lost 2 of my 6 Pearl Gouramis that have been with me since the beginning three years ago.

Here's the techie bit: Ammonia 0, Nitrate 0, Nitrite 0. pH 8.2 kH 9. Incoming tapwater is pH 7.8, kH 14.

I clean the tanks every week, hoovering the substrate, clean the walls if necessary, clean the filters every 4/5 weeks, scrub the tank paraphernalia and the water change is in the region of 40% each time. I have a limited number of plants (never seem to be successful with them). The water is well filtered as I keep a spare filter running in that tank and also have a small spray bar filter running for oxygenation purposes. The lights are on 4 hours a day. I feed a varied diet, alternating between Fish Science Tropical Granules, Sera Veggie Flakes, Fluval Bug Bites and NTL Probiotic granules. I tried frozen food cubes but found the waste rate a bit high. The substrate is sand over a black gravelly type of plant substrate.

The same regime is applied in the smaller, successful tank, where the only difference is there are fewer plants, and the substrate is just sand. In this smaller tank I had only one unexplained death (a gold Gourami) and two accidentals where a Black Widow Tetra jumped out of the tank, and a Cory got stuck between some rocks.

I feed twice a day, two small pinches which disappears promptly.

Any ideas what I'm doing wrong?

 

[Colin_T]

Pictures of the fish?

Do you feed the rainbows any plant based foods or plant matter?
Rainbowfish need at least half their diet to be plant based.

What do the rainbowfish look like before they die?
eg: do any of them stop eating, swell up like a balloon, do a stringy white poop and gasp at the surface or near a filter outlet?
If yes, they probably have Fish TB

Guppies, platies and other common livebearers coming out of Asian fish farms are regularly infected with intestinal worms and gills flukes. Deworming all your fish in all your tanks would rule out intestinal worms and gill flukes as the cause of death.

Section 3 of the following link has information about deworming fish.

What to do if your fish has Stringy White Poop.

Fish do a stringy white poop for several reasons. 1) Internal Bacterial Infections causes the fish to stop eating, swell up like a balloon, breath heavily at the surface or near a filter outlet, do stringy white poop, and die within 24-48 hours of showing these symptoms. This cannot normally be...

www.fishforums.net

 

[Fox46]

Thanks for an informative response and the very useful references.
The Rainbowfish didn't swell up or exhibit any symptoms - they just expired over a long period of time. The one remaining one looks fine. The only plant based matter that the Rainbows ate was the veggie flakes, probably twice a week at most, and they never showed any interest in peas or courgettes when I added them to the tank, but I'll give it another go for the remaining one.
The Platies that died did appear to have slightly swollen pale bellies, and if I can get the opportunity I'll post a pic of the one that I think is next on the list for expiry. I see trailing pale poop fairly often so I'm focusing on the worming issue after what you said.
When I bought the Platies I asked for all females but there was an errant male in there who once reaching maturity managed to get round the rest of them in record time so I've been slow to pick up on the swollen bellies as fry began to appear in the tank, thinking they were either pregnant or retaining eggs for a later delivery. I see that a couple of the 3 baby Platys that emerged from his activities (and survived) look a bit pale around the stomach area possible indicating distension.
I have some Esha ndx - I see it says 1 drop per 1 litre - any easy way of converting that into ml per litre?
Many thanks for that.

 

[Fox46]

I have some Esha ndx - I see it says 1 drop per 1 litre - any easy way of converting that into ml per litre?

Ah, I found a calculator on line. It says 7.3ml. Sorry.

 

[Colin_T]

1 drop per litre is 1 drop for each litre of water.
There isn't 7.3ml in a drop. Check your figures so you don't overdose and kill everything.

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To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

There are 3.785 litres in a US Gallon
There are 4.5 litres in a UK gallon

There is a calculator/ converter in the "FishForum.net Calculator" under "Useful Links" at the bottom of this page that will let you convert litres to gallons if you need it.

When you measure the height, measure from the top of the substrate to the top of the water level.

If you have big rocks or driftwood in the tank, remove these before measuring the height of the water level so you get a more accurate water volume.

You can use a permanent marker to draw a line on the tank at the water level and put down how many litres are in the tank at that level.

Remove carbon from the filter before treating with chemicals or it will adsorb the medication and stop it working. You do not need to remove the carbon if you use salt.

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Feed the vege flakes every day. Try to grow some duckweed (small floating plant) in the tank and the rainbow will pick at that. They also graze on algae growing on the glass or plants. If you don't have any algae in the tank, increase the lighting time 1 hour per day and see if you get some green algae growing on the glass and ornaments. If you still don't get any after a couple of weeks, increase the lighting time by another hour a day and see how the algae goes. You can have the light on for up to 16 hours per day but most tanks only need it on for 10-12 hours a day if they have live plants.

A fat belly in livebearers can be baby fish developing or intestinal worms. It's regularly worms and if the fish do a stringy white poop and die while fat, it's usually worms.

 

[Fox46]

drop per litre is 1 drop for each litre of water.
There isn't 7.3ml in a drop. Check your figures so you don't overdose and kill everything.

I meant the calculator said that a 166l tank needs 7.3ml in total.
Thanks for the additional info. I'll up the veggie flakes and try to maintain more plants. I already have algae on the ones I've got.

 

[Essjay]

I think eSHa intend you to use the dropper in the lid and count drops. But it is very easy to lose count with 166 drops.
They do say that for ndx 100 drops = 4.4 ml so 166 drops = 7.3 ml as you said.

Is that 166 litres the amount of actual water in the tank or what the tank manufacturers give as the volume? The manufacturer's volume includes the thickness of the glass and the air space above the water. Then you need to take into account the volume taken up by the substrate, decor etc.

 

[Fox46]

 

[Fox46]

The paler Platy above is the one that's next on the casualty list I think. I'll adjust the dose of the Eshe ndx downwards to accommodate the points mentioned. I notice in the instructions for Eshe that when you do the water change you're not supposed to use dechlorinators on refilling. This isn't going to kill off the bacteria in the filters is it, using untreated water to refill?

 

[Essjay]

eHSa say that in all their instructions. Possibly it's because so many water conditioners contain something to detoxify ammonia and/or something to 'stimulate the slime coat' both of which could interfere with the medication. I use API Tap Water Conditioner which does neither of those things.
In their FAQ's their answer to "I don't see any results" contains the phrase "The effectiveness can also be influenced by (excessive) use of water conditioners" - my bold. Maybe that's why they say not to use it, in case people overdose water conditioners.

If you are concerned, if your water company uses chlorine and not chloramine, you can let tap water for the water change stand for several days to allow the chlorine to gas off, though that means having enough buckets and somewhere to put them.

 

[Fox46]

Done the first treatment with eSHe ndx. I'm reading different recommendations on re-treatment. I understood from the link that it should be repeated once per week for 4 weeks. The eSHe leaflet says repeat after 14 days in the case of oviparous Nematodes (how would I know what it is?) and in cases with little or no improvement do a 50% water change (with no dechlorinators) and repeat treatment. How soon would I expect to see an improvement?
(Incidentally, I've realised that the tank with only one health-related (as opposed to accidental death) is almost entirely stocked with mail order fish (from Covid days). That prompted me to check all recorded deaths in both tanks and I see that over 3 years Mail Order fish totalled 6 deaths, one LFS =31 deaths, and another LFS = 5. And of my currently depleted fish stock across both tanks, 14 are Mail Order fish, and 8 are LFS.) I think I know where I'll be re-stocking from.)

 

[Colin_T]

I don't know why the company would suggest not using dechlorinated water but that is just bad advice in my opinion. If you add chlorinated water to an aquarium containing beneficial filter bacteria or livestock (fish, shrimp, snails, etc), you risk killing them. Chlorine and chloramine both kill fish, shrimp, snails and filter bacteria so any water that is added to an aquarium containing livestock, must be free of chlorine/ chloramine before it's added to the tank.

Deworming medications should be treated once a week regardless of the instructions on the packaging. There is no way for the average person to differentiate between different types of round worms (or flat worms) so just do it once a week for 4 weeks. This will kill any worm larvae that hatch from eggs and get rid of any adult worms in the fish and tank.

Both the platies in the picture above look fine to me. What makes you think one is about to die?

The colour on the praecox rainbow is nice

 

[Fox46]

The paler one in the front seems swollen compared to how it was, and like the others that predeceased her, her stomach has turned much paler than the rest of her.. Even the new fry (3 survivors) have pale stomachs quite clearly defined as though they are distended. The Sunsets don't look so swollen and are uniform in colour, but for the past few days all 4 adults have been hiding away, only emerging to feed, the palest one barely at all. I don't see any bullying going on. I'm not confident that any of the 4 adults will survive but repeating the treatment for 4 weeks sounds the best bet. Thanks

 

[Colin_T]

If the fish are hiding after treatment, it's usually caused by an overdose of medication. A big water change will normally fix that.

With deworming medications, do a 75% water change and gravel clean the substrate 24-48 hours after treatment.

 

[gilpi]

Reading your first post, two things that raised a red flag for me. First, that all your readings are at ”0” even the nitrates. Second, cleaning the filters every 4/5 weeks, it takes that many weeks or more to cycle a filter. Not sure exactly how you clean your filter but an uncycled system can stress your fish which in term can cause the fish to weaken and be more susceptible to diseases.