Backyard Aquaponics
A place to discuss aquaponics

This past two weeks has been a nightmare... First my Koi started to float upside down, which I figured out is because of my system design where my water level dropped too much when the GB filled up before draining back (Ebb and Flow). No Sump
I had a 100L glass tank and 40L GB with gravel media. In the meantime I reconfigured by adding a 210L drum (the kind used in the Barrelponics setups) as the Fish tank and now the old glass tank is used as a Sump.

Meanwhile the fish continued to die one by one, one a week. I figured it to be due to the swim bladder that got damaged with the water level that changed rapidly in the old system configuration I used. As a futher remedy I stopped feeding them pellets for a few days and only fed them a few canned peas which I made into a pulp before throwing into their tank. But the dying continued....

This morning I discovered a new nightmare, clear stringy mucus stuff hanging from the pipes to the air stones. Now I'm at the point of just asking WTF!?!?!!!

I started with 9 small koi about 5cm (2 inches) in length each on 9 November 2013. I added a Plecostomus about 30cm (12 inches) just for good measure and a good batch of Biofilter sludge when I started the system in November. All went well over November and December, but last week in January when they started floating upside down, I did the change over to include the 210L drum. But all have been downhill from there onwards. I'm left with one Koi and the Plecostomus as per this morning

PH 7.2
NO3 is about 5mg/l
NO2 is less than 0.3 mg/l

My tomato plant, Spinach and Green pepper plants are growing beautiful, we've even had harvests already in the past 3 months.... But the fish.... Eish

Any words of wisdom please?

P. S. Before I added the 210L tank into the design my Nitrate readings was a constant 100 mg/L +. This tank cycled within two weeks due to the Biofilter sludge I added on day 1 and this I did not anticipate, so my GB was not up to the task at hand since the beginning. The plant growth has been so incredible though (especially the tomato with it's famously massive root system) that I think that plus the added 210L stabilised the Nitrates over the past 2 weeks.

Air and filtration keep constant air in the system and ensure your water is well filtered. Ensure that there is no sunlight on your water to encourage the film growth. Change 50% of your water.

As you said the damage may have already been done and you may have to restock.

I had the same problem a while ago. after a lot of research and elimination it turned out to be a single cell parasite.

are your fish flashing? rubbing their sides on the bottom of the tank often?

are there any bloody patchs on the ones that die. mine didn't always have that but it was common.

the only solution I found was 5ppt salt. so 5 kgs of salt in 1000 liters of water. a lot of your plants will hate this.