Fishes Dying slowly - one by one

[Tazman13]

Hi Guys
I'm new here and am posting out of desperation. Apologies for long post.

Background: I have kept a freshwater tank of African cichlids for over 1 year with hardly any casualties and was really enjoying the hobby.
A few months back I went overseas for a couple of weeks and had left my fishes in the care of my neighbour and an automatic feeder. When I returned I realized the neighbour only visited my home on the day of my return and found most of my fishes dead.
Since then I've tried and tried unsuccessfully to keep my fishes alive.

My water change schedule is atleast once every week of about 25-30%.
Latest water parameters -
Ammonia - between 0.00 and 0.25 (I don't know why I keep getting this reading - maybe the test is old?)
Nitrite - 0ppm
Nitrate - between 20 and 40ppm
pH - 8.0
Chlorine - 0ppm

Symptoms of fish that are not well and then subsequently die within a couple of days:
Breathing heavy and not eating. Usually the same fish would be coming to the front and top for food. They also seem to be shy and sit at the bottom looking tired.

I have a 300L / 80 gallon (4x2x1.5ft) aquarium with coral sand as substrate. Most of the cichlids are Malavi (peacocks) of around 8-10cms (before going overseas I had over 20. I've tried adding fishes since coming back but none of them survive. Currently only 4 remain). However, I do have 1 10cm clown loach (who survived when I had gone overseas) and a pictus catfish (around 15 cms).

The dead fish show no signs of being beaten and are showing full colour.

My feeding schedule is twice daily and only that the fish can consume in 1 min.

Currently I have 2 filters running - the larger one with around 3kg of matrix and the other smaller one with ceramic noodles that I had got with the filter.

I had upgraded the tank from 3ft to 4ft only a month before going overseas and during that month there were no casualties or symptoms of any fish being sick or distressed.

I've been combing these threads religiously to find an answer but to no avail.

I also appreciate that most fish issues are due to water quality and overstocking or feeding. However, the clown loach and pictus catfish (both sensitive fishes) have survived without any issues.

Please help as to what have I been doing that is causing the fish to die.

 

[Coursair]

I would test your Tap water as well.

Consider doing a bigger water change
50%

Make sure you aren't tossing out filter media. Rinse in tank water or dechlorinated tap water.

Don't add more fish till you get things stabilized.

Can you post a pic of the tank ?

What temp is the water ?

What are you feeding ?





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[Coursair]

Malawis should be on a mostly veggie based diet I believe. I would get the Pictus and Clown Loach out as they prefer schools and need a meatier diet.

Malawis can get Malawi Bloat from incorrect diet...just a thought.

Not accusing you of feeding wrong, just wondered.

I fed ours Zucchini and Romaine as well as Omega One Algae Wafers and Spirulina based foods.


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[Autumnsky]

Welcome to the community. Hoping we can offer some answers or help.

So very sorry this is happening. It is heart breaking.

Trips away from home, and friends, neighbors and fish sitters are hazardous to the health of the little aquarium friends very frequently.

*******

Your parameters seem alright - now. So that is maybe a start.

(I'm not from the Cichlid side so as for the fish themselves, I might not be that much help)

The first thought is that the chances that the fish feeder machine might have over fed. That said, the NitrItes are often deadly, even after the NitrItes have been taken back down to 0.

From my reading (also disclaimer - not a scientist or chemist) the effects of the damaging NitrItes injure internal organs and fish can die days & weeks later from the NitrIte poisoning.

You provided a very lengthy, though necessary bunch of info.

A couple things other wise I am wondering about.

As for your filter media...
do you wash /clean it in tap water?
Do you change the filter pads very often?
Did you use your old media when changing tanks?

When you changed the tank did you change the substrate?

What is the GH & KH of the tank?

Did you see anything BEFORE your trip?

I am wondering if after the tank change you had a mini cycle, and it wasn't as big of issue because you were doing pwc? Not feeding as much as the auto feeder.

Even if the auto feeder wasn't feeding WAY too much the ammonia could have spiked, causing some deaths which could have caused more issues and more deaths. Then less fish to eat the food... more issues.

As a side note you probably know quite a lot about fish, but consider reading through the article in my signature, it is easy to learn a new thing or two. There are more links to some additional articles.

One of note and an area of note, would be to read Fish-in Cycling: Step over into the dark side - Aquarium Advice the section "fish in" cycling of the article in my signature.

Also get Prime water conditioner if you can to help neutralize any possible issues with water quality.

What are the parameters of the water the day before you do a pwc? Possibly start doing pwc every 3 days or 2 times per week.

Also do the fish have the proper lake salts needed by them? There are additives specifically created to supplement each types needs like "Lake Victoria". (Beyond that tid bit I am out of my knowledge base with what kinds they need.)

 

[Tazman13]

Thanks for your reply. I'll go home and post a pic of the tank. I have done a few big water changes as well since my overseas trip (which was 3 months back).
I feed them the regular NLS cichlid pellets and spirulina wafers. I put in a cucumber or zucchini every now and again as well.
I've never owned a thermometer but keep the heater between 26C and 28C.
Filter media and foam are always washed with tank water.
So frustrated and sad with the fish dying regularly.

 

[Tazman13]

Photo of the tank

Photo of the tank