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About 4 days ago my black fin catfish shark slowed down on his eating then the next day looked a little darker. He is now almost black instead of silver/gray. I keep the aquarium as salted as I can without hurting my live plants and cory. The only recent changes I can think of would be I added some algea destroyer to the tank to help kill some type of beard/hair algea and bought a bigger power filter 100gph to 200gph. Watched the water cycle after the filter change and I was careful enough the tank did not cycle.
Any Ideas?

Thanks Jason
20g tank


Attached Image:

Hi,
Is this the critter:
http://www.aquariumfish.net/catalog_pages/brackish_water/shark_white_tip.htm

There was another site that said something about it turning
black if "happy".

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

That's the critter.
Do you remeber the the site(happy)?
I googled but can't find it, but I'm still looking.

Thanks for the fast reply
Jason

Hi,
It turns out I missquoted the tag line.
Here is what the leader says:

Quote:
Silver-tipped Shark, Hexanematichthys seemanni, Shark Catfish ...
You can tell alot about this type of Shark's health by their color and fins. They seem to turn a darker shade (almost black) when feeling a bit under the ...

animal-world.com/encyclo/fresh/catfish/sharkcat.php

http://animal-world.com/encyclo/fresh/catfish/sharkcat.php
Endquote

Sounds like the rest of the sentence is "under" the
weather?

Here is the site:
http://animal-world.com/encyclo/fresh/catfish/sharkcat.php

You will have to "explore" the site to see where the
tag line comes from. I don't see it on the lead page.

Frank

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

This morning he died.
Thanks for responding, though.
Jason

They need more salt as they age , about sg 1.015 or more. I doubt cories could live at that level of salinity,most Hexanematichthys seemanni prefer to go to coastal waters as they age.

They are often described as brackish fish ,presumably to make them easier to shift to freshwater hobbyists, but as they get older its probably more true to say that they are marine fish capable of spending short periods of time in lower salinities. They do live in estuaries and tidal rivers, but that means they can travel to higher salinity occassionally, and take periodic breaks from certain salinities, and then go back to exploit feeding areas later, but in an aquarium that is just impossible.Some will make it in brackish conditions and some wont. Its probably better not to keep this species again until the option of running a tank with higher levels of salinity is easier for you.

A catfish may mature at differing rates in an aquarium, perhaps he was older than his size would have you believe.In any case, there is no real way to tell what the fish requires in terms of salinity on a month by month basis, and the species is bound to show a degree of variability in this requirement, perhaps not only in terms of regional distribution of the species, but possibly also from individual to individual.

This is also a fairly photosensitive species and can be easily stressed when lights go on and off quickly, and that can add metabolic problems and immuno suppression into the equation.

I have read on many occassions that many people believe that light levels might have a bearing on normal maturation,since the catfish has some hormonal reaction to both water quality and light levels, and this too would affect the required salinity needed, and the overall health of the fish. Some people obviously get lucky, but I think this is one of those fish that requires the expert touch to keep alive. Not by any means an easy fish to keep , like many fish that mature from freshwater to salt, they are not always the best candidates for pets and are better limited to public aquaria.