# Fish Behavior



## Tabatha (Dec 29, 2007)

I just read an article in Aquarium USA 2009 Annual which I wish I'd read before I acquired my first community aquarium, "The Inner Fish" by Miller Morgan.

I can't speak for everyone but I can certainly speak from my own experience and some of you may or may not agree, some may benefit and some may not.

Simply because a fish is labeled as _"peaceful"_ and a _"good community"_ fish, doesn't mean they can't be predators. We had purchased cardinal tetra and harlequin rasbora as some of our first community fish as well as male and female Endler's livebearers. We were so excited when our first batch of fry arrived, little did we know that tetra and rasbora thought they were tasty little snacks! What a shock! And little did we know those tetra and rasbora were doing us a favor because it wasn't long before we were overwhelmed by a population explosion!

It doesn't matter if they're living in a South American stream or in your tank, fish are just being fish and their instincts are ingrained genetically. It's sometimes difficult for us humans to understand why the littlest, weakest fish is being picked on in our tanks, why we scold the bullies and try to save the weaklings. We're placing our personal human values on creatures which don't share our point of view and in reality, it's ridiculous for us to do so.

Another excellent point this article makes are the labels we place on fish in terms of temperamnet, "aggressive", "peaceful", etc... These are judgments we make "that have no place in nature, where all behavior has some eveloutionary significance..."
_"The difference between us and fish is that despite our differences in personality and cultural background, we're all pretty much the same in terms of the basics -- but not so with fish. The differences among fish are many -- everything from changing sex and how they breed to being in schools or alone to survive. A group of people in a room from different places and backgrounds can result in interactions both positive and negative, but these people will go back to their own homes and neighborhoods. When fish from different kinds of habitats are in a community tank, they are home."_​


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## Chris S (Dec 19, 2007)

Those tetras are darn-right nasty to fry!


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## Tabatha (Dec 29, 2007)

Chris S said:


> Those tetras are darn-right nasty to fry!


So I learned! No one warned me of this and I haven't found anything in literature about it either.


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## Westender (Mar 24, 2006)

If you look at tetras and piranhas, they have very similar mouths...

And until recently, they were all classed as Characids. 

When I worked in retail, I had a love / hate relationship with the easy / moderate / difficult and community / non community stickers that went on the tanks. It's really difficult sometimes to explain the suitability aspects of mixed community fish-keeping. Fish can get along fine from a temperament status, but have to be segregated due to water conditions or food or a massive number of parameters. And some fish function well in a community as long as they are in large groups, but put them in small numbers and hello mass murder! Some fish grow too large or too fast... And of course, no rule is set in stone. I once had a planted tank with cardinals and Aplocheilus lineatus that functioned wonderfully. Until one day I had to drain the tank and I put them all in one bucket and ended up with 4 very fat golden wonders and one terrified cardinal.


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## Shattered (Feb 13, 2008)

Those are some great points. I never agreed with the LFS "community / Non-community" stickers as well. The question I'm always left with is; What would you replace the stickers with? 

When I'm selecting fish, I always try to remember that aquariums are an attempt at replicating nature. That way I do my research and then double check it and then throw it all out as it might not work out in my case.


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## Tabatha (Dec 29, 2007)

Unfortunately there are many, many, many people who don't do their research and don't want to/can't be bothered for whatever reason.

I typically Google everything I'm interested in but sometime the results are conflicting from one site to the next but there are always common elements. That's when I turn to forums for advice.

With cichlids however, temperament is relative to other cichlids, not community fish in general and, unless you already knew that, you might purchase a SA cichlid for your SA tank which might prey on the other inhabitants, unbeknownst to the purchaser.


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## Shattered (Feb 13, 2008)

Tabatha said:


> Unfortunately there are many, many, many people who don't do their research and don't want to/can't be bothered for whatever reason.


I guess this is where we have to make a distinction between a customer and a hobbyist. The "sticker" system was designed for the typical customer, while hobbyists are the ones who do the research.

One of the best online tools I use is Tim's tropical compatibility charts


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## Tabatha (Dec 29, 2007)

Shattered said:


> I guess this is where we have to make a distinction between a customer and a hobbyist. The "sticker" system was designed for the typical customer, while hobbyists are the ones who do the research.
> 
> One of the best online tools I use is Tim's tropical compatibility charts


Nice point and thanks for the chart link!


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## Tabatha (Dec 29, 2007)

After briefly checking that site, I would say that it has good *suggestions* but I wouldn't take it as gospel.

Rams and Angels are both South American species yet the website indicates that they are not compatible. I have Bolivians living with Angels in a 90 gallon, neither bother with the other. Angels occupy the middle to top of the tank and the Bolivians sick to the bottom.

I think other factors may come into play such as tank size.

Edit: I just wanted to back up my statement that Scalare do indeed cohabitate and share the same habitat with Mikrogeophagus in the amazon river: http://fish.mongabay.com/data/ecosystems/Amazon River.htm


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## Shattered (Feb 13, 2008)

Tabatha said:


> After briefly checking that site, I would say that it has good *suggestions* but I wouldn't take it as gospel.
> 
> Rams and Angels are both South American species yet the website indicates that they are not compatible. I have Bolivians living with Angels in a 90 gallon, neither bother with the other. Angels occupy the middle to top of the tank and the Bolivians sick to the bottom.
> 
> I think other factors may come into play such as tank size.


Sorry, I should have specified that. That is pretty much what he says at the top of the chart.


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