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Sudden Aggressive behaviour

The Don

Member
Joined
20 Jun 2014
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43
Has anyone ever experienced spontaneous aggressive behaviour from their communal tank mates? I introduced some small tetras similar to neons but without the red pigment. Normally I'd expect them to school in with the other tetras, Having purposely selected and kept a peaceful community tank. But they didn't and as you can imagine they became obvious newbies as they looked smaller and vurnable. Next day after lights off I expected peace or death from stress.. But they all seemed fine minus some fin nips. Tonight i put in some stress Zyme and I see anarchy, the Siamese algae eaters eating my shrimp and then other peaceful tank mates like blood thirsty pack of dogs attacking each other
 
Having purposely selected and kept a peaceful community tank.

Then you probably already were misinformed about that where ever you got it.. The Siamese algae eater is one known for long for it's agressive tendencies towards tank mates when they becomes an adult. Quite common behaivor among several loach spieces to be agressive towards simular spieces or everything comming near. Especialy if kept in too small environments.. Lots of people get misinformed about that in the lfs, only if you ask. Someone would easily believe everything sold there is a peacefull community fish and the name tag on the display tank doesn't say much about requierments and behaivor. And if you ask, the answers honnesty is still rather aimed towards sales numbers than the animals faith.

And that's not your fault, the customer and fish are both victims in this case.

Bottom line the mayority of loach spieces sold are not realy suitable for aquariums smaller than 200 litres. But that's my personal opinion.. Even the most valued databases around give minimal requirments , which are often very marginal and in many cases still need a big questionmark.
 
I find the genuine SAE not aggressive if the tank is well planted and minimum 3feet ,confusion arises I think when the territorial flying fox is wrongly sold as the SAE
 
Just trying give a opinion as to what my be going on@The Don,its difficult as their is no clarity on your tetras,species etc,the shrimps could be a initial water quality issue or something like behavour issues,as mentioned fin nipping which can panic tank mates. Like adding something like Tiger Barbs or Serpae tetras but the description is different.Maybe as Zozo indicate incompatable fish ,check back at retailer
 
Well if in a fish spieces behaivor and compatibility description is said

"Can display particularly high levels of aggression towards similar-looking species."

Then this also "Can" mean it is not necessarily always the case and if you are lucky it doesn't occure at all.. If you are less lucky you might get an individual which is extremely grumpy and maybe far-sighted too and attacks everything that comes near.
 
281FB5C0-DCCF-4CAF-BD32-59D04B694639_zpsjbjetvns.jpg

One of my two SAE. @zozo would you identify them as real SAE?
48FB3985-628D-4020-9BBC-C95932B64377_zpsoow8g6ym.jpg

The new neon type tetra and one of the remaining shrimp @PARAGUAY
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my tank (apologies recently started dosing liquid carb and the plants are adapting)
 
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You probably just one of those unlucky examples that proves the rule and got a grumpy sae pecking on others than it's own. What many people forget and even many others just do not want to acknowledge is also fish do have a personality and individual charactars. Many have a pecking order and develop a structural heirarchical relationship in the group in which they live.. This behaivor only can develop within a community if the induviduals involved have a degree of cognitivity. It more than just an instinct.. :)

And in particular with the loach families which probably all have a heirachical pecking order many people come to find out that the general discription about behaivor which in general is breefly descibed as peacefull community fish, is not always to describe as breefly as they do and their is much more to it.

Something like fish psychology yet doesn't realy excist it's hard to say why yours isn't playing by the rules. Maybe your sae is frustrated and bored and missing a few mates to peck on and looks for other victims instead. And driving the rest of the tank crazy.. Did you ever observed what's going on after lights out? Usualy the party gets realy goin at those hours.
 
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zozo is on to something here I think. Take your tank you have quite a cosmopolitan mix.Some quite passive and in the wild would probably spend their entire existence in darker shallows whereas here although it's well planted its dominated by very brightly coloured substrate. Also some fish often contradict their description,like you have silver tip tetras books refer to them in sufficient numbers as peaceful, but often they can be quite unpredictable often the first fish to react by upsetting inhabitants by a bit of fin nipping or generally boisterous upsetting small neons or similar fish. My experience with SAE if your tank is large enough and they are well fed and if room add a few comedians like small barbs they tend to behave well for their size (but if peckish something like a shrimp would look tempting? )the barbs not notorious types(tigers etc)seem divert their attention,my own observation only.But also as zozo says individuals can have characteristics what defy their description,little is known about this aspect
 
I got this with my little pea puffer, now these are also known to be very unpredicable.. I got mine as a little juvenile and all started out very peacefull. It was introduced to a little schoal of 7 very active high fin barbs a school of rasboras and cherry shrimps. He grew up with them and probaly just sees them as his tank mates, he is peacefull towards them. But crearly demands respect and sometimes claims his space.. The rasboras are never in his path he doesn't look at them, but the barbs live with in his layers around him and know him and respect him. It's like they sence when puffy got out off bed with the wrong fin and starts the day grumpy, than avoid his path, it's like the barbs learned to read his body langauge, the barbs shoot away when puffy says get out my way.

All fish i introduced at a later stage, while puffy is slowly getting an adult.. He doesn't accept them in his territory. I already had to rehouse 2 different species i introduced later to the tank because the puffer started to chase them continiously. I do not know how else to describe, but observing it, it is like the new introduced fish just do not know him. And probably do not give him the respect he demands. They move to much into his space and this he doesn't take for very long.. And then after a few weeks trying to demand his respect he decides they have to be removed from his territory if he doesn't get it. And thats the intire 110 litres.. He rules the tank, if he decides the have to move and he chases them constantly around the tank till he's tired, rests a few minutes and goes on the chase again. And to prevent to much stress and maybe even a kill, i have to remove the fish to another tank. And when they are removed all is back to normal again and puffy is victoriously cruising around. Probably thinking he finaly chased them off..

I realy have to stop trying to introduce new spieces to this tank, i have no more room ijn the other tanks to rehouse any more fish. It's puffy's tank now not mine, till now he decided enough is enough. :)
 
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when you add fish to an established tank, expect some upset; especially in terms of bullying to newcomers. Best way to avoid is to pick suitable species, and/or re-arrange decor, add at lights out
 
After watching the tank past couple of nights I've re homed 7 blue tetras today. Seemed to be the main starters of the aggression. Similar to @zozo story of the other fish didn't dare get in their path. Only the first evening lights on and you can see the difference already, everyone has free passage to swim freely.
 
After watching the tank past couple of nights I've re homed 7 blue tetras today. Seemed to be the main starters of the aggression. Similar to @zozo story of the other fish didn't dare get in their path. Only the first evening lights on and you can see the difference already, everyone has free passage to swim freely.
A good idea is to have a agreement with a local aquarium shop to return fish if a purchase doesn't go to plan,they are usually ok with this when they get to know you as a customer.Hopefully your tank will settle down now
 
After watching the tank past couple of nights I've re homed 7 blue tetras today. Seemed to be the main starters of the aggression. Similar to @zozo story of the other fish didn't dare get in their path. Only the first evening lights on and you can see the difference already, everyone has free passage to swim freely.

If you read the description http://www.seriouslyfish.com/species/knodus-borki/ it's a valid candidate causing agression and stress in the tank.. With choosing such characters you always need not only to look at characters of the other species also the region they like to go around, like top level, mid level or bottom level of the tank.
In terms of numbers you might think your tank is not overstocked, but if all live in the same level it still might be the case and fish can feel cramped up and will result in agressive behaivor towards eachother.

They do not nip fins for the fun of it, it is a form of territorial comunication and a sign of stress, ussualy for fish which are cramped up and are in eachothers space to much.

In time if you do your homework and proper observations you'll learn, not only to choose fish which can go together but also how setup a tank for them, with choosing the right planst and hardscape suitably for the size, shape needs and behaivor. Create hide outs, hang outs, shelter, break lines of sight etc.

For example if you have a fish sp which like to live in the upper regions of the tank, then give it some surface vegitation, this doesn't absolutely need to be something floating but it also can be a large java fern attached to hardware close to the surface which creates a overhang with it's long leaves kinda floating. Then you will notice that fish loving the surface hang around there becuase iot makes them feel safe. That's what they do in nature, under floating vegitation or close to the shore under overhang from marginal plants.

Imagine as a bit overdone example.. If you were hardcoded by nature to feel safe close to shelter, because you are low at the food chain. Would you feel safe if you were put on a mountain meadow with no trees and shrubs in sight for miles?
 
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