# Swimming Space



## jameson_uk (10 May 2018)

A lot of articles talk about fish having plenty of swimming space but I am now wondering how to take that?

Would you say this is just tank size or areas of open water?

My tank is pretty much a big jungle and with all the plants and wood there isn't actually much open water.  I am wondering whether the fish might prefer areas where there is no hardscape or plants (or short plants anyway) rather than always been within the plants.


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## Edvet (10 May 2018)

I would prefer an open spot to feed and have the fish interact, and lots of cover around for them to retreat/hide if they want, I dont think a fully grown tank is a big problem.


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## jameson_uk (10 May 2018)

I really need to get my DSLR out as the camera on this temporary phone is crap.





I was wondering about removing the large anubias on the right hand side as it has quite a bit of GSA and other algae after changing the lights.  I also thought about possibly removing the bit of driftwood nearest the middle to free up some space.

Part of my thinking is based on the behaviour of livestock.  Before the plants grew out the corys would school over the substrate but now there isn't large areas of substrate exposed in any single area so I only tend to see 2 or 3 together and these seem less confident.  The black neon tetras also seemed to be more active and now seem to spend more time in the plants.  I used to see them swimming where as now they tend to make much smaller movements.

I do wonder whether having space as well as cover does affect their behaviour?


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## castle (10 May 2018)

jameson_uk said:


> Part of my thinking is based on the behaviour of livestock.  Before the plants grew out the corys would school over the substrate but now there isn't large areas of substrate exposed in any single area so I only tend to see 2 or 3 together and these seem less confident.  The black neon tetras also seemed to be more active and now seem to spend more time in the plants.  I used to see them swimming where as now they tend to make much smaller movements.
> 
> I do wonder whether having space as well as cover does affect their behaviour?



I think you've got this the wrong way round, large schooling is normally because they're less confident - safety in numbers etc. Now you've got decor providing shelter, their schools are smaller as they feel safer, my guess anyway.


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## jameson_uk (10 May 2018)

castle said:


> I think you've got this the wrong way round, large schooling is normally because they're less confident - safety in numbers etc. Now you've got decor providing shelter, their schools are smaller as they feel safer, my guess anyway.


Probably not the right explanation from me.  The corys would often scavange as a group but they were reasonably confident.  Now they seem more skittish than they were before.  With the neons it is less the schooling but more the swimming.  Previously they you would often see them swimming and exploring the tank where as now they seem far more sedantry and often just sit in the plants.


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## dw1305 (11 May 2018)

Hi all, 





jameson_uk said:


> I was wondering about removing the large anubias on the right hand side as it has quite a bit of GSA and other algae after changing the lights. I also thought about possibly removing the bit of driftwood nearest the middle to free up some space.


That is still quite a lightly planted tank, there are very few small fish that aren't happier among, or very close to, vegetation. 
Have a look at <"which fish breed....."> and <"Splash Tetra - _Copella arnoldi_">





jameson_uk said:


> Before the plants grew out the corys would school over the substrate but now there isn't large areas of substrate exposed in any single area so I only tend to see 2 or 3 together and these seem less confident. The black neon tetras also seemed to be more active and now seem to spend more time in the plants. I used to see them swimming where as now they tend to make much smaller movements.





castle said:


> I think you've got this the wrong way round, large schooling is normally because they're less confident - safety in numbers etc. Now you've got decor providing shelter, their schools are smaller as they feel safer, my guess anyway.


That's it, when they feel secure the fish will occur as ones and two's and spend a lot of time "chilling" among the plants. 

Stressed fish will shoal more tightly and often swim around really actively, this is because they are trying to find a safer place and there is some safety in numbers. In a barer aquarium they never find any cover and they just keep swimming around. 

cheers Darrel


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## sciencefiction (12 May 2018)

Fish do require some cover but it does not need to be excessive.
Healthy and happy fish will be active and exploring the area. They will not act skittish or stationary...
Fish do prefer larger tanks and plenty of open space, there is no doubt about that. 

My corys for example are now in a large tank that has little cover. There is no underwater plants. It's the happiest I've ever seen them, not because there is no plants but I am guessing because they have the type of substrate they like and plenty of space to explore, I had previously kept them in a tank with lots of plants and small gravel as substrate before and as much as I don't want to admit it, they prefer this bare sand only tank in comparison....They sift non stop.....as before they used to gather behind plants in the previous tank and just sit around doing nothing at all until I feed them, and yes, they used to be skittish enough.  If you see corydoras habitats, they live in open areas with a sand bottom...no plants...

I also have a group of harlequin rasboras. They tend to stick together when swimming around although in very loose groups but they're not skittish. They come over to me the moment I approach the tank begging for food.  There is a difference between fish feeling stressed and darting around in groups and fish just exploring the tank. Fish should be exploring the tank...Will you see fish sitting in one spot in nature?

I think you have the right for concern that the fish are not overly happy and if it were me, I'd make the necessary changes to alter their behavior positively, whatever that takes...They substrate you have is also not ideal for corydoras. .


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## sciencefiction (12 May 2018)

To add to the above, have a look @zozo "Mission Bathtub 2018" journal below..

Fish are very curious creatures. And they're constantly on the go when happy, exploring around. 
You can see that in one of Marcel's videos below, happy curious fish. He has a video on page 3 but the entire thread is worth reading, very interesting. 

https://www.ukaps.org/forum/threads/mission-bathtub-2018.52227/page-3


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## PARAGUAY (12 May 2018)

That’s the confusion when automatically entering a Aquarium Shop seeing a tank full of tetras or barbs example shoaling and except that when taking home they don’t More often than not it’s a survival strategy There is a couple of good articles about this in PFK magazine. South American different types tetras gathering in huge numbers for feeding and going their separate ways in the secluded shallow water and one studying Bronze Cory catfish coming from cover secluded spots to feed in huge groups zig zagging their way through open water and back again splitting up into smaller groups


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## sciencefiction (12 May 2018)

dw1305 said:


> That is still quite a lightly planted tank, there are very few small fish that aren't happier among, or very close to, vegetation.
> Have a look at <"which fish breed....."> and <"Splash Tetra - _Copella arnoldi_">



I love the Splash Tetras, really nice and interesting fish.



PARAGUAY said:


> one studying Bronze Cory catfish coming from cover secluded spots to feed in huge groups zig zagging their way through open water and back again splitting up into smaller groups



We all know corydoras don't school....They are social fish though, so are a lot of other fish but some are true schoolers...
Based on my experience I can tell you corys do not hide or stay in secluded areas if they're happy. They're out and about...going all over the tank and if there's driftwood higher up, they'll go as high as the driftwood goes to "sniff" around. Some of mine go into the planting baskets positioned near the surface of the water. 

What you don't want to see is a bunch of corys sitting tight in a corner or behind decor, etc...and not moving much....Or tetras, rasbporas or barbs sitting on one spot hiding....To illustrate what I mean, sick fish tend to detach from the "school" and sit lonely behind filters, heaters, etc....This doesn't mean that fish that hide are all sick, just trying to explain....It is very possible that some fishkeepers have never truly seen their fish being happy, especially if said fish were kept in exact same tank/conditions all the time. So what they've observed is what they think is natural for the fish....
Thankfully, due to some tank breaks, the same fish I own moved several tanks and several setups and i was able to observe behavior changes as I changed tank sizes and tank conditions....

Also, breeding is not always a sign of fish being happy. Breeding can be a surviving mechanism as my corys bred in a tank ridden with ammonia of 8ppm + that stunk the house, while their fins were literally melting in front of my eyes.....I was extremely surprised at the time. For the record I did manage to save all corys at the time and they subsequently bred again and produced offspring that survived. 

Having said that, if a tank is planted to the brim, the fish will technically always be in hiding as they've got nowhere else to go....Do they like living in a tank "overstocked" with plants, I don't know....I think it very much depends on the species and what they encounter in nature....


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## PARAGUAY (12 May 2018)

I agree they are not schoolers in the true sense but they are happiest in their own company, the article was about a study of them in the wild were they would stay in shade under overhanging trees branches vegetation in groups and swim out in very large numbers zig zagging into open water stopping starting feeding and then retreating back to the shade.I agree though different behaviour will occur in aquarium situations.


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## sciencefiction (12 May 2018)

For the same reason otocinclus tend to live among corydors in nature, using them as protection but the videos I've seen is both species swimming freely in open space, occasionally darting to the surface for air....When I kept otocinclus in my 100G tank, they were extremely active...not much sitting around at all and if you browse this forum the opinions on ottos behavior differ....Mine literally played around the tank, in the air pump flow, doing circles on the glass, cleaning up leave surfaces and moving from spot to spot like butterflies, etc...and they're very fast swimmers. They're like rockets in big open area....Then my tank broke, all ottos went into a small tank. They all perished in a matter of months. They were very stationary while in there...I previously had them for over 4.5 years. I don't think the would have died if they still lived in the 100G.

In aquarium settings corys don't school...They just go around the tank non-stop in singles and couples perhaps...Out of the 8 years I kept corydoras, I've only seen them that active for the last year and a half, when living in large open space...So yeah, corydoras hiding and sitting in one spot is what I used to previously observe but same corys now are on steroids...moving and sifting non-stop. I wonder if they stop at night time as I never see them sitting on one spot anymore...Hence I've had change of opinions and saying that "some fishkeepers may have never seen their fish truly happy!"....As i was one of them.....


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## sciencefiction (12 May 2018)

All corys need seems to be natural river sand, a few leaves and some driftwood...There isn't much cover and there aren't any plants. It is the exact same thing I noticed with mine, they feel "safer" in open sandy areas...


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## dw1305 (13 May 2018)

Hi all, 





sciencefiction said:


> All corys need seems to be natural river sand, a few leaves and some driftwood..


Yes, it really depends upon their natural habitat. Fish that come from flowing water will behave differently from those from still water.

Even among the Dwarf cichlids, _Biotecus sp._ and _Apistogramma diplotaenia _will inhabit areas of sand, even when cover is available.

You also have to bear in mind that all these videos are filmed during times of low water, and that the fish may behave differently when water levels are higher, moving away from the main water channels into areas of inundated vegetation.

cheers Darrel


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## zozo (13 May 2018)

sciencefiction said:


> occasionally darting to the surface for air



That's what it looks like..  But Oto's and Cory's both are distant members of the lungfish family, i believe it was after examening bone structure they discovered this. Though both species do not have lungs anymore but fully developed gills instead and this gulping for air behaivor seems to be an ancient genetic marker still active in the species but no longer required for survival nor functional in any way.  Nothing but a nice Trivia, fun to know....


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## Tim Harrison (13 May 2018)

Otos are a fairly diverse group and I guess behaviour varies accordingly. They posses digestive tract adaptations that allow them to "air breath" it's a diagnostic trait of the genus apparently. Loricariids are mostly facultative air breathers but I've heard/read somewhere that may not be true of all oto species...some maybe obligate air breathers


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## sciencefiction (13 May 2018)

Well, my point is, knowing that corydoras like sandy areas, one should try keeping them for some period of their life in a more open sandy tank and then see where they behave best...My first cory tank was pretty much just sand and some driftwood, very few plants. They did great. Then they bred and I put a bunch in a gravel and heavily planted tank. They lived but were skittish in there and hid a lot. Of course they didn't sift the gravel at all. After some patchy period of my life and both my big tanks breaking one after another, I lost a lot of them but the survivors are again in a open sandy area and are the happiest ever. Personally, I'd not keep corys any other way. Plants are great but there are plenty of other non-bottom fish that will do better in heavily planted tanks. For bottom feeders I think going emersed and keep the bottom less crowded is best.


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## sciencefiction (13 May 2018)

Tim Harrison said:


> Otos are a fairly diverse group and I guess behaviour varies accordingly. They posses digestive tract adaptations that allow them to "air breath" it's a diagnostic trait of the genus apparently. Loricariids are mostly facultative air breathers but I've heard/read somewhere that may not be true of all oto species...some maybe obligate air breathers



It could be something to do with species because both corys and ottos are occasionally found in drying pools devoid of oxygen/very low oxygen, as the sole surviving species...even though both in aquarium setting would do better in more oxygenated tanks..


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## sciencefiction (13 May 2018)

I was just browsing for random stuff but came across the below thread. Look in post #11 where the corys are  Sometimes a picture is more than a thousand words..



 

https://www.ukaps.org/forum/threads/towing-the-line-discus-120x50x45.37535/#post-405221


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## zozo (14 May 2018)

Tim Harrison said:


> Otos are a fairly diverse group and I guess behaviour varies accordingly. They posses digestive tract adaptations that allow them to "air breath" it's a diagnostic trait of the genus apparently. Loricariids are mostly facultative air breathers but I've heard/read somewhere that may not be true of all oto species...some maybe obligate air breathers



There indeed seem to be much more to it than only an ancient gene still active.. Must have been a very outdated statement i red about the catfishes lungfish relation and their gulping behaivor.. If you search for "Aerial respiration in catfish" you'll find a lot more resent study material going into the subject.. Corydoras aneus is a regularly occuring test subject as many other sp. of catfish.. Very interesting..  Using a part of their stomag as O² uptake source and their gills to vent off CO².  


> Facultative air-breathing responses in different species. Facultative air-breathing doubtlessly increases the survival probability of fishes forced to endure periodic exposure to water unsuitable for aquatic respiration. During the tropical dry season, for example, fish that typically occur in normoxic flowing streams may become trapped for weeks or months in stagnant ponds that are hypoxic and hypercapnic (Lowe-McConnell, 1975; Kramer et al.1978). Moreover, the inhabitants of some tropical ponds may have to endure hypoxia every night irrespective of season (Kramer et al. 1978). In recent years the category 'facultatively air-breathing fish' has been expanded by discovery of and experimentation with various species


https://pdfs.semanticscholar.org/6259/07f54ccf0aec42bd0c7c6091170949a2bcb6.pdf


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## jameson_uk (12 Jun 2018)

This started off seeing a huge tank at Chester zoo.  In there they had loads of fish and the thing that stood out was the huge schools of neon tetras.  There were large driftwood islands with java ferns on but the fish were very much swimming around the ferns in open water than in them.

Just cleaning tank now and removed the bigger bit of driftwood.  The black neons are now schooling in this big gap.





Re-reading the above I probably overstated the fish. Whilst they were hanging around in the plants they never seemed stressed or particularly unatural.

Now wondering whether to put the large bit of driftwood back or not (or to swap it with the smaller , taller piece)


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