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I have noticed with my SAE's 1st thing in the morning the black strip is pale, but after a short time of light and moving the strip is dark as can be be, they are in great shape eating well.
ammonia, nitrite 0: nitrate 5: ph 7.8 to 8.
I read on another posting, that the fading of the strip was a bad sign so now I am worried. This is pretty typical for my 2 SAE. They share the tank with danios, cories and rainbows.

A little night fading is normal,as long as they are back to normal colour within an average of half an hour after lights on. Its during the day you have to watch for it. Its possible if the tank hasnt much aeration but does have plants that there may be a slight oxygen defecit. Plants consume o2 when not under light, some tanks have quite high differences in day to night oxygen saturation. That combined with the slower metabolic rate while sleeping may cause an SAE to fade a little more at night than usual. I used to have one SAE in particular that slept suspended in the water flow from a hydor ario airpump, and he never really blanched his stripe out.

In fact heres his "alien abduction" picture to prove the point. The piccie is upside down for joke purposes BTW)

http://i12.photobucket.com/albums/a245/longhairedgit/IMG_6459.jpg

Most fish retract some of the blood in vessels immediately under the skin while dozing at night, it just helps them to save energy in the hours when they will be sleeping and not feeding. It also helps if you have iridescent scales as many fish do, not to have them working reflectively at night.The pigment that backs the scales rather like silver compounds back a mirror, and when keen eyed predators are about , who are on the lookout for red, green or blue iridescence, is an advantage to cut the blood flow off to the pigment cells, thusly decreasing your night visibility. If youve ever turned on your tanklights suddenly in the night or used a torch to look at your fish youll see often even normally very colourful fish may have faded to blacks greys and whites.

To be safe just make sure you have sufficient aeration on at night. It helps keep the filter bacteria steady too. Most tank crashes happen at night, especially if you happen to be close to overstock limit.

If the tank is well equipped , its probably just the SAE acting normally and nothing to worry about.

An extreme example of colour change during sleeping is Beckford's Pencil Fish, Nannostomus beckfordi. During the daytime, the fishes have a horizontal black stripe, with the males displaying bright red colouration in areas where it is absent on the females (the gender difference in colour is obvious in this species). Let them sleep for a while in total darkness, then hit the lights suddenly and you'll discover the horizontal stripe has vanished and been replaced by three oblique stripes ... !

So it doesn't surprise me that SAEs undergo at least some change in appearance during the night, for reasons outlined by LHG above. Though why the Beckford's Pencil Fish undergoes such an extreme change is still something of a puzzle to me ...

Incidentally, if I make the mistake of hitting the tank lights too early after a dark night during the winter (when here in my part of the UK, it can be nearly 9am before it's properly light in the morning by the time we hit the Winter Solstics) my Cardinals are no longer iridescent, and the blue colouration has become an intense, though strangely matt, purple hue that occupies the area below the dorsal fin, but spreading mot much further. The red colour is still present however. An example of LHG's observed 'shutting down' of iridophores to mask the fishes from nocturnal predators.

Mind you, such colour changes are of little protection from predators equipped with electric field nagivational and tracking capability such as Black Ghost Knife Fishes, Gymnotid Eels etc. Which is why it's a bad idea to put such fishes in with small companions. In the case of Gymnotid Eels, it's a bad idea to put them in with anything, even another member of their own kind, unless the aquarium is truly colossal because they are viciously territorial, pugnacious, and cannibalistic to boot. Which, given the attractive patterning of Gymnotus carapo, for example, the bomb proof hardiness of Gymnotid Eels and their ability to survive equipment failures courtesy of their accessory air breathing capability, is a pity, though the adult size of 2 feet makes them a specialist fish for the 'oddball' collector with prior experience in maintaining fishes of such size. Despite the bomb proof hardiness of Gymnotid Eels, novices are advised to steer clear of them, not least because any attempt to integrate a Gymnotid Eel into a community aquarium will result in disaster as the fish sets about turning it into a species aquarium by eating the other occupants ... a little tangential diversion before returning you all to normal service.



Panda Catfish fan and keeper/breeder since Christmas 2002