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Psychological influence of fear?

926 views 12 replies 5 participants last post by  Anorea 
#1 ·
I have a sick/bloated fish and have been doing daily small wc, past two days giving this one fish an epsom salt bath as well. Noticed since bringing them home (almost a week now) all the fishes lay low most of the day, only getting active in the evening when it is darker. I thought they were just still getting used to their new home... They are always a bit active after the wc in the morning, then lie low again.

Today when I happened to remove the gallon of tank water I needed for the salt bath, (replacing w/new making the water change) everyone hid from the disturbance. Had to do something else came back 15 min later to catch the sick fish- everyone still acting timid. After I caught the fish and put it in the bath, all the others are swimming around the tank acting normal. So now I am wondering if they have been cowering all day because this sick fish is making the rest of them feel afraid? Because when she is out of the tank for a short while all of a sudden there is all kinds of activity.
 
#3 · (Edited by Moderator)
All prey-type fish. Five tetras, two swordtails.

She was in the bath for 30 min and then another 20min readjusting- I poured portions of tank water into her bath at intervals so just over 50min total. During that time I was often walking close to the tank and the other fish didn't startle, swimming around interested in each other, like I'm not there.

The moment I dipped a cup holding her back into the tank, it's like I flipped a switch. All the fishes are hiding low in the plants again, and if some start to venture out, they dart back out of sight when walk by the tank.

Looks to me like her illness and/or fear is making the rest of them feel scared or stressed out.
 
#11 ·
Very informative, someoldguy, thanks! "Schreckstoff" sounds like the name of a Heavy Metal rock band. 😂
While reading the first article, it occurred to me that they were looking at the evolution of the wrong trait, that the evolutionary development wasn't in the sending of the signal (because sending the signal was far less likely to benefit the sender), but in the ability to detect the (incidentally sent) "signal" as an indicator of a threat, which much more directly benefited the individual that possessed that ability. Then I saw where that more direct and simple explanation (evolutionarily speaking) was addressed in the brief of the second article, so I didn't bother to read it since I had already understood that point on my own.

Very interesting and potentially useful observations. I bet a synthesized version of the "Schreckstoff" would be a lucrative proposal as a gamefish attractant for anglers. Infuse it into artificial bait or spritz it onto lures and watch those big predator gamefish come a-runnin'! (Or maybe that was mentioned in the second article which I didn't read?)

Olskule
 
#9 ·
No problem . Way back , I'd occasionally get a tank that had 'fright disease' where the fish would dash randomly around the tank at the slightest provocation .
The general consensus at the time was that it was caused by something undetectable in the water , maybe pheromones released by the fish themselves . That second article suggests that the old guys in the fish clubs back in the '80's may have been on to something .
 
#12 ·
Not so long ago I read a book about fish behavior. It described how in some gamefish hatcheries (trout, I think) the young fish were being lost at a high rate to predators when released, because they didn't know to avoid them. So to teach them they expose an adult, wild-caught fish to sight of a predator, then take out some of the water the adult fish was in, which had the "alarm substance" that fish gave off. Then they exposed the young fish to view of the predator and the water with alarm substance at the same time. When released into the river, the young fish remember what predators to fear from that "alarm substance" water.

I think the initial experiement had a control, where they exposed young fish to sight of the predator without the water the older fish had been in. These fish did not learn to fear and avoid the predators.

When I saw my fish acting like that I remembered this.
 
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