Barra deaths

[Wal100]

Hi

I have recently lost a couple of Barra ranging from 150mm to 250mm. Water temp at 25deg C and all nutrient levels well within spec.

I have a heater in my tank maintaining water temps.

On the last couple of dead fish I have noticed some skin blemishes, see attached pics.

Any of you folks have any ideas for me?

Thanks Wal

[RupertofOZ]

What are your overnight water temps... how many fish, how much water, how much filtration???

[Wal100]

35 to 45 fish
Water consistently at 24 deg C
1,100 litres pumps 24/7 flood and drain
2 x Gb's with a volume of 660 litre
3 x hydro channels with 18 plant spots
Ammonia, nitrite and nitrate in spec
pH 7.5
CF 22

[RupertofOZ]

Ammonia, nitrite and nitrate in spec

What does "in spec" mean???... actual values please...

[Wal100]

Ammonia 0.25 ppm
Nitrite 0 ppm (very close to this on the colour chart)
Nitrate 120 ppm

These levels have been the same for months with no deaths... system running for 9 months

[RupertofOZ]

Nitrates are high... but not unacceptable.... and suggest that you could have a lot more plants....

Was that 2 grow beds totalling 660 litres... or 2 grow beds, each having a capacity of 660 litres??

[DaveOponic]

How's your aeration? Have you noticed the Barra at the surface? The only time I lost Barra was when water became slightly dirty. At that time I relied on water reentry to the tank for aeration. I didn't notice any external damage to fish but two fish died after just looking listless and staying at bottom of the tank. I now use 10 airstones to thoroughly aerate and a swirl filter to keep water clean.

From my experience Barra do well in very clean water with lots of dissolved oxygen and never overfeed them.

I don't bother with all the measurements these days. No fish deaths in my tanks for over 12 months now.

Dave

[RupertofOZ]

I was going to get around to aeration Dave... just wanted to establish the rest of the parameters first... ;)

[Wal100]

I have more air than you can poke a stick at... from air stones to air lifts circulating water, falling water and GB return water.

[RupertofOZ]

Well maybe, as suggested on BYAP... they've burnt themselves against the heaters...

You've got a couple of pretty big heaters working full time overnight from memory.. to keep the temp up...

[Yabbies4me]

Hey Wal,

Looking at the pics, I would agree that it looks like they've been burnt by the heaters, but the question in my mind is: Were they alive or dead when they were burnt?... because I reckon the burns may have happened after the fish had croaked.

The shape of the burns looks like a direct contact burn and I couldn't see a healthy fish getting close enough to the heater, for long enough, to get a burn like that. I would imagine that once they got close enough to feel the heat that they'd move away from the heater before they made actual contact. Not only that, but I also think that being in water, they'd have to make contact with the surface of the heater for some time to suffer such a burn.

Where are your heaters mounted, are they sitting flat on the bottom of the FT?... because the burns on your fish are high up on the body, I would've thought too high. The only way they could be up there was if the fish were on their side when they contacted the heater, such as a dead fish floating around. Or if your heaters are mounted vertically to the sidewall of the FT as you would in an aqaurium, then the burn on a live fish would be running top to bottom on the body, not lengthways.

Just my observations, but something to consider.

Cheers, Yabbies.
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