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FAQs on the Rainbowfishes Behavior
Related Articles: Rainbowfishes, Fishes
at the rainbow’s end; An
introduction to the Atheriniformes, the rainbowfish and silversides
by Neale Monks
Related FAQs: Rainbowfishes 1,
Rainbowfishes 2, & FAQs on:
Rainbow Identification,
Rainbow Compatibility,
Rainbow Selection,
Rainbow Systems,
Rainbow Feeding, Rainbow Disease,
Rainbow Reproduction, |
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Funny blue-eye behavior - had to share! 11/10/08
Good afternoon to the WWM Crew!
I was doing a water change this weekend, and as usual, my tank being in a rather
dark corner of the room, I put the lighting strip, still on, on the stand behind
the tank, letting it light the tank from behind/below so I can see what I'm
doing. I was refilling the tank when I noticed my single remaining blue-eye
(Pseudomugil furcatus) swimming on her side... I thought it was really weird and
I was slightly worried, until I noticed she was trying to keep her back towards
the light. Well, now I know how this species finds the surface of the water! It
was quite a strange sight, though, seeing her skim the glass-made vertical
"surface" of the water... poor thing... Don't worry, I put her sun back where it
belongs ;-)
With all my best wishes, and many thanks for the immense service you provide,
Audrey
<Hi Audrey, good to hear from you! Fish do indeed use a combination of light and
gravity to detect "down". It is a familiar experiment in ichthyology to put fish
in an aquarium and then rotate the light around it. Even though the fish
can feel, by gravity, which direction is down, it also orients itself so its
back (dorsal surface) are pointing towards the light. At first glance this
sounds silly. Why not rely on gravity alone and keep the right up and down
orientation? The reason for this "dorsal light reaction" (as it is called) is
because fish have camouflage that helps them hide from predators. They have dark
dorsal surfaces and light undersides. From above, the dark dorsal surface
matches the deep dark depths, while from underneath the light belly matches the
sunlight. If the fish failed to orient itself, it's camouflage would be ruined,
and it would become easy prey. So the fish makes the changes it has to, keeping
its camouflage working properly. Fish are indeed much cleverer than we sometimes
think!
Cheers, Neale.>
Mean Dwarf Rainbow
Hi there,
<Hello Jennifer>
I've looked through your FAQ's and can't seem to find anything about this.
I have a 12 Gallon Eclipse system that's been running for about 4 months now. I
initially started with 4 dwarf Rainbowfish, 2 male and 2 female,
<Mmm, would have been better with one male, three females... and this tank is
too small...>
at the suggestion of the aquarium store employee (another employee later told me
that you shouldn't cycle a tank with rainbows, but that's not the problem
here). Almost immediately we noticed that the largest male was constantly
picking on the females, and wouldn't even let the other male swim around the
tank (he had to hide in the rocks or behind the filter, poor little guy).
About a month later, one of the females developed a sore on her side and looked
like she was going to die, so we returned her to the pet store. The large male
Rainbowfish continued his relentless harassment of the other two fish. Two weeks
later, the other female died. And then finally, the smaller male died. Now it's
about a month after the small male died, and the large male is still in the tank
all by himself and seemingly doing just fine. Water quality checks out ok,
but we do have a bit of a brown algae problem. So, I don't know what to do now.
It seems like that fish is just mean and doesn't want to have any
tank-mates. I'm a little miffed at him for killing off the other three fish! I
would really like to have an aquarium with two or three different types of fish,
but now I don't know what to do.
<I do... trade him in... start with a new livestock plan>
If I return him to the pet store, do you have any suggestions for my
setup? (Our water is slightly hard with a slightly high pH).
Thanks much for your help. I really love your site. :-)
<Ah good... then read it over to make up a list of possible organisms... that
stay small, are apparently compatible... and check with us, others re their
disposition with each other. Bob Fenner>
-Jennifer
Colorless Boesemanni Rainbows 7/8/06
Hello. I have looked all over and haven't found anything like my
question. About 3 weeks ago I bought 4 Boesemanni Rainbows from a LFS. All the
rainbows in the tank were silver with only hints of color.
<Likely just young... really don't "color up" till are a good two plus inches in
length>
In a display tank there were 3 or 4 rainbows with beautiful colors, so I knew
they were capable of colors. I specifically asked if the ones in the tank would
get color, because they looked nothing like the ones in the display. The guy
that I asked I have talked to before, and he seems to know what he's talking
about. (I've compared his answers with you guys' and others) He said that they
were probably stressed in a small tank with a lot of fish, and with the nets
fishing around; they would get their color when they were more secure and
settled.
<This is also a factor>
Another thing he mentioned was that they might not be mature yet. (3 of the 4
that I got are 3 1/2 inches or so, and the 4th is maybe 2 1/2 inches, so I would
think that at least the 3 should have decent color.)
It sounds good, right?
<Yes>
It's been 3 weeks and they still are silver, for the most part. I have seen
them get dark vertical stripes (but not totally dark blue/purple) and
sometimes they have a darker yellow tail, but the color never stays for
long. They've never looked like the pictures I've seen of Boesemanni. They are
in a 75 gallon tank with 5 Congo tetras, 7 longfinned Danios, 2 dwarf Gouramis
and a Plecostomus. The water is within safe parameters on the test strips
(even ammonia), and none of the other fish are picking on them. I can't figure
it out. Would more plants/rocks/hiding places help? Or do I just give them
more time?
Thank you for your time and thoughts.
Alicia
<Well... there is some hope that these will improve with time, good care and
feeding, but there are instances that without good "upbringing" that Rainbows
(among other life) are more permanently "decolorized" from poor care... Only
time can/will tell. Bob Fenner>
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