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Thread: Fish dying of fright?

  1. #1
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    Fish dying of fright?

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    Never thought it is so easy to frighten fishes to death!

    Well, the story goes:

    I had a tank of more than 100 Apistogramma borelli frys in them. It is a bare tank execpt for some floating plants and a sponge filter. They were removed from their mothers when they're about 1-2 wks old, and have been raised in this tank for more than a month.

    As they grew up into juveniles, I find some interesting phenomenon. Whenever I go nearer suddenly, some of them would seem startled and started dashing about, and eventually seemed to have comatosed, loosing their balance and spiral downwards to the bottom. Most recovered, but some then stopped breathing and died.

    I know it is cruel, but I had tried pulling this trick a few times and it worked all the time.

    Damn, didn't know these guys have weak hearts. Some of them darkened before they die, as the fight or flight syndrome seemed to have caused melanin dispersion due to the activation of the sympathetic system.

    Anyone had such an experience?

    Cheers,

    Kenny

  2. #2
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    Hi

    Change their diet. Cylops and spirulina may be the way to go. It may be a fatty acid or vitamin deficientcy.

    Good luck

  3. #3
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    Tyrone,

    They have been on a varied diet, ranging from daphnias, to BBS, to frozen bloodworms.

    There's another tank with juveniles of the same age, but have been left to brood by their mothers in a heavily planted tank, show no similar problem. Due to their environment, they do not get startled even if I approach them suddenly, which I often do as my brinshrimp hatchery is hanging on this tank. These are also fed on the same diet.

    Perhaps you're right. Together with a predisposing factor in nutrient deficiency, the unfavourable environment (ie. bare tank) could further affect their cardiac efficiency due to the nervous stimulation.

    In your opinion, what nutrient deficiency would have led to this problem?

    Cheers,

    Kenny

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    Perhaps it isn't a deficiency, but a surplus of something.

    Years ago, I had a similar behaviour in a tank of youngish FIL. After I lost them all and was tearing the tank down, I discovered why.

    The tank had gradually turned acidic, which was rare in my hard water in Santa Clara, and I had left some lead plant anchors in the substrate. They were nearly etched away, and hindsight gave me the strong clue that the fright and spiraling were very likely due to neurological damage from heavy-metal poisoning.

    Wright
    01 760 872-3995
    805 Valley West Circle
    Bishop, CA 93514 USA

  5. #5
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    Hi Wright,

    Yeah, the only difference between this tank, and the other 'normal' borelli tank, is that the fry tank gets a water change twice a week, with water straight from the tap, although declorinator, dechloraminator and heavy metal binding agents are used.

    Heavy metal poisoning does cause neurological damage. why didn't I think of that?

    Cheers,

    Kenny

  6. #6
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    Kenny,

    Fish and fry in particular die from fright easily. I don't believe it's got anything to do with diet. It's due to environment or in your case, the tank itself. Fish in bare tanks don't feel secure and if the tank is covered on all 4 sides, it's even worse. Fish, by nature tend to fear what comes from above so if the tank is covered on all 4 sides, someone who simply peers into the tank from the top can send the occupants to fish heaven.

    I once saw one of my Discus die from something which looks very much like a heart seizure. My daughter jumped in front of the tank and the Discus immediately went into a spin. It spiralled upwards and when it reach the surface of the water, it became motionless and sank to the bottom of the tank, dead. It was a healthy fish when it died.

    My friend who works in Underwater World in Sentosa as a diver told me a story a few years back. Seems like a drunk tourist banged the side of one of their glass tanks. The fish were still okay after a few hours but the next day, they were all dead.

    Loh K L

  7. #7
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    Hi Kwek Leong,

    Yes, I heard such stories from my vet friends too. Even jittery fishes like arowanas do get muscular spasm after a shock, such that their back curved up which make them look like an S shape from the top view. Left alone for a couple of days to weeks, they usually recovers by themselves.

    Not only fishes, but I heard that animals too, eg. the gazelles or antelopes, do suffer from muscular spasms when they're being chased and cornered, and sometimes become comatosed. THat's what my vet friends used to tell me, which doesn't seem so funny to me anymore...

    Well, I certainly hope it is not due to heavy metals or something like that....


    Kenny

  8. #8
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    The fright factor has been used to explain some fish deaths but heavy metal poisoning does occur sometimes as Wright has mentioned.

    If the pipes in your block are old, they may have been copper pipes. Water that remains in the pipe prior to being used by you may contain traces of copper and perhaps other metals if they had come into contact with it earlier.

    I usually let the water run off for awhile, say a quick one minute run to flush out the initial water that should be concentrated with some traces of the metals. Of course this water doesn't go to waste. Sometimes I take a bathe before I change water for a tank so usually I turn on the tap a few minutes after I've finished my bath. Then I'll do the water change. Waste not, want not.

    Fish can be rather afraid when viewed from the top but some fish and fry when kept in a tank with lots of fellow occupants usually don't die from fright. Those that usually become more shy are those that were raised from young in a tray away from areas with human traffic. As such they become unaccustomed to having peeking eyes peering at them.

    When somebody knocks the glass of a tank, the resulting "soundwave" in the water can really interrupt the receptors on the lateral line. This may disorient the fish in a such a way that it causes nervous stress and eventually spells the death of the fish. A slight tap will not kill them most of the time but a heavy knock may.
    Fish.. Simply Irresistable
    Dawkinsia assimilis, Heros efasciatus - Looking for Pelvicachromis taeniatus
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