Colombian shark behaviour?

[Sara1210]

Hiya everyone,

My 3 colombian sharks are growing nicely now. Spot and chopper being around 4 inches and Jack being 5-6 inches. Over the past couple of weeks I've noticed Jack and chopper going frantic when I open the lid, they have “their corner” in the tank lol and when I open the lid they swim side to side up the side of the tank with the dorsal fin pointed right up, they do this sometimes when they taste their food go in the water too but lately Jack has started to flip out the surface of the water.

Sometimes if I go up to the glass without opening the lid they do it to. Are they pleased to see me or are they telling me to get out their tank? Lol

Sometimes when they dig up the sand I flatten it back out with my hand and if they come over I take my hand out till they swim off again (not fast) but Jack has been known to make me jump and whip my hand out the tank incase he was trying to sting me lol

If this is territory, have I brought it on myself and is there anyway I change it?

[MatsP]

I think they are doing "wagging the tail and jumping up" that a dog does when it hears you open a tin [whether it is green peas, baked beans or dog food usually doesn't matter]. In other words, they have learned that you coming to the tank means "we'll get food". Several types of fish that I keep/have kept has learned to recognise when I walk up to the tank means food.

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Mats

[Sara1210]

I've just fed the sharks there dinner, then I always hoover up what they don't eat, tidy up the tank then switch the lights off. I do this every night.
Tonight I fed them, hoovered up, put my hand in to flatten out the sand and the sharks started thrashing about so I took my hand out, quite rapidly if I'm honest lol then my partner put his hand in and they were fine, they swum to the other end of the tank and sat there till he took his hand out then swum back over. I then put my hand back in to finish what I was doing and they done it again, my partner then kept his hand in the tank while I finished straightening the sand and not a thing. Why are they doing this when I'm in the tank. They aint used to my other half being in the tank, he doesn't do anything in there normally, I don't get why they freak out so much when I go in there???

[RickE]

Maybe it's your fishy pheromones

Seriously, they won't hurt you just by brushing against you. You would need trap them against something to get enough pressure to cause you an injury from one of their spines.

[MatsP]

I don't think they are "freaking out" (at least not in the "stand on a chair and scream 'mouse'" kind of way).

They recognise that you provide them with food. You could probably hand feed them.

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Mats

[Sara1210]

I don't think they are "freaking out" (at least not in the "stand on a chair and scream 'mouse'" kind of way).

They recognise that you provide them with food. You could probably hand feed them.

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Mats

Really? what makes you say that?

[MatsP]

The fact that they are not afraid of your hand - but they seem to connect it with food. Try holding a piece of food at the surface of the water and see what happens. This may actually help keep the food going into the fish, rather than having to be tidied up later.

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Mats

[Sara1210]

I tried it and they acted alert like they normally do when they taste food go in the water but they they just hovered just above the sand. They didn't come up

[MatsP]

Keep trying, and they will probably get there.

--
Mats

[Richard B]

If you want to hand feed, then try, try, try again. Maybe starve them for a few days first so they are really hungry.

I'm not fussed about hand feeding by my big female

synodontis granulosa

does without a second thought, even though i'm not expecting it.