Peacock Eel Floating?  3/18/09
Dear Crew,
<Hello,>
In my 30 gal tank I have had a ~9 inch peacock eel for years who is generally happy and shy and hides in the plentiful plastic plants and small rock caves. When threatened, it burrows into the round pebbles but
normally is comfortable enough to just hide in the plants. The other fish (various tetras, Leaffish, algae eater, swimmers, etc) leave the eels alone.
<Not a big fan of pebbles in Spiny Eel tanks: sooner or later the fish gets scratched, and then secondary infections set in. Small species like Macrognathus siamensis should be kept in tanks with smooth silica sand. Do see here:
http://www.wetwebmedia.com/FWsubwebindex/matacembelids.htm>
Recently it became so bloated that it floats when still, so has to anchor under some plants or position itself under rock ceiling. I change water and vacuum every 2-3 weeks and chemistry is OK except nitrites/nitrates can occasionally get on the high end of acceptable. I add aquarium salt according to directions.
<How much salt? And why? Macrognathus siamensis isn't a brackish water fish, and while there may be value to salt as a therapy under some situations, continual exposure to salt can cause problems for freshwater fish. One reaction is bloating, and indication that their osmoregulatory system has been overloaded in some way. Unless you're keeping one of the truly brackish water species, like Macrognathus aral, there's no need to use salt.>
Other fish in tank get flakes. Ran out of frozen bloodworms for eels and switched to frozen brine shrimp for the last month or so. I hand feed this eel and my other younger peacock eel. Every now and then I put in some pieces of cooked egg or salmon for variety.
<Don't use egg. Not a natural part of their diet, and can cause constipation.>
I have noticed some bubbles coming from the big one's anus on two different occasions so wondering if this is just a bad case of gas that will work itself out or if something else is going on.
<So far as I know, spiny eels aren't air breathers, so I wouldn't expect them to expel gases out of their vent in the same way as certain air-breathing fish.>
Ready to lay eggs?
<Possibly; female Spiny Eels are distinctly laterally compressed because they are substantially deeper bodied than the males. Sometimes, certain fish become egg-bound in captivity if not kept with males: even if the eggs don't develop into fry, the simple act of spawning "clears out" the female reproductive tract.>
I adore my eels and would appreciate any help you can give.
<Very difficult to say precisely what the problem is. As mentioned above, there are at least three possible factors. Gravel simply doesn't work with spiny eels in the long term, and nondescript bacterial infections are the almost invariable result. The regular addition of salt to freshwater aquaria causes more problems than it fixes, and isn't recommended because it can cause precisely the sort of bloating problems you're experiencing here (see, for example, Malawi Bloat). Finally, egg binding is an occasionally reported problem among species of fish that refuse point-blank to spawn in captivity. While there isn't much you can do about egg binding beyond adding a male and hoping for the best, I'd also recommend treating with a suitable antibiotic (e.g., erythromycin or Minocycline) while adding Epsom salt at a dose of 1 teaspoon per 5 to 10 US gallons. These will have the combined effect of (hopefully) killing the bacterial infection while
restoring the osmotic balance within the fish. Stop with the regular salt though!>
Thanks very much!!
Dianne
<Cheers, Neale.>

Peacock Eel looking pale   2/3/09
Hi,
I have a peacock eel who is becoming very pale, almost pinkish, and his spots seem to be transparent. He's about 6-8'', and I've had him for a year now in a 55 gallon tropical tank. I've had past problems with bacterial infections due to sick feeder fish, and over the course of several months lost the majority of my fish. The eel never seemed affected though. I treated it and decided to change my tank to African cichlids since I only had 7 fish left.
The tropical tank was kept at 80 degrees with a pH of 7.8. I had colorful decorations with dark blue and purple pebbles. The eel was always the typical color, light brown with a lighter belly and dark eye spots. When I changed to a cichlid tank 2 days ago, I changed the dark larger gravel to a sand colored crushed coral which upped the pH to 8.2, temp is still 80 degrees. I also added some brown flagstone for the cichlids (I only have 4 yellow labs under 2"so far). The eel has been very active since the majority of fish were lost, and he eats well. His behavior hasn't changed
since the tank was switched over, there are no sores and his skin is smooth and intact, but his color has definitely paled.
My question is this: Can a peacock eel change colors to better match it's surroundings? or, Could it be the pH? I really love my eel, and want to do whatever I can to keep him healthy. I would hate to know I'm causing him to
fail in this tank. Any advice would be appreciated.
Thanks, Beth
<Hello Beth. The answer to your specific questions are [a] yes, fish do change their colours somewhat, depending on their mood and environment; and [b] pH is possibly an issue here. But let's expand this slightly. Spiny Eels are notoriously prone to bacterial infections, and shouldn't be brought within a mile of feeder fish. End of story. Whether or not they actually eat the feeder fish is immaterial, simply putting feeder fish in the tank is an unacceptable risk. Secondly, Spiny Eels are very easily damaged by anything other than smooth sand. Gravel and pebbles are totally
unacceptable for the smaller species. Most people who try eventually end up with a dead Spiny Eel. This happens so often I just consider it mandatory to keep the small Macrognathus species Spiny Eels in tanks with a smooth
silica (silver) sand substrate. Always take care not to use things like Tahitian Moon Sand as these are "sharp" sands. The manufacturers actually state that these sands are incompatible with burrowing fish, but too many aquarists ignore this, and wonder why their Spiny Eel gets shredded and eventually infected with a bacterial infection of some type. Crushed coral is inadvisable for a variety of reasons; partly because it raises the pH and hardness, and partly because Spiny Eels can't burrow through it. Coral sand could be mixed with silver sand at a ratio of up to one part coral sand to four parts silver sand, but any more than that would also raise the pH and hardness excessively. There are Spiny Eels from Lakes Tanganyika and Malawi, but the Peacock Eel (Macrognathus siamensis) is not one of them, and consequently has no place long term in a Rift Valley Cichlid aquarium.
Even if the water chemistry won't kill it immediately, the aggressive behaviour of the cichlids will, either directly, or through making it difficult for the Spiny Eel to feed. The native Spiny Eels are "used" to cichlids and actually prey on them, or more specifically, their fry. They don't burrow but instead hide in the rocks, and while not commonly traded
they are available from time to time. If your Spiny Eel has changed colour, my gut feeling is that this may be partly to "blend in" but could equally easily be a stress reaction. This fish doesn't belong in this tank, and shouldn't be kept with Malawi cichlids, period. Do see here:
http://www.wetwebmedia.com/FWSubWebIndex/spinyeelsmonk.htm
Hope this helps, Neale.>

Re: Peacock Eel looking pale (Time to get creative!)   2/3/09
Thank You,
<Most welcome.>
Here's my next question...
I don't know anyone with a tropical tank I would trust not to kill my eel.
I'm also afraid to give it to a fish store just to suffer elsewhere. Do you have any suggestions for where I could look if I need to give him up?
<The best advice is to get in contact with a local fish club. Many have an online forum, so even if you can't travel, you can still communicate.
That's probably your best way to learn the better stores or fishkeepers in your area. I'm in England, so my knowledge of the aquarium hobby in Florida is somewhat limited!>
I spoke with at least 4 different fish store guys (not Petsmart) all told me the eel would do fine in the cichlid tank.
<It's possible they were thinking of the African species of Spiny Eel, such as Mastacembelus ellipsifer, which do indeed cohabit with (some) cichlids quite well. But the reality is that people sometimes know rather less than they think they know. It's always important to research topics independently, though stuff that's been edited by experts, whether books, magazines, or web sites like this one. In this case the problem is that, for example, Malawi cichlids and Spiny Eels need completely different food.
Mbuna are mostly herbivorous, but will eat meaty foods if offered, and this makes them sick if given to excess. Spiny Eels are carnivores, but slow ones, so most insect larvae or whatever put in the tank will be eaten by Mbuna long before the Spiny Eels find them. Again, the pH and hardness suitable for Malawi cichlids is much to high for Asian Spiny Eels. Yet again, the cichlids want coral sand and lots of rocks, whereas the Spiny Eels need soft sand and feathery plants. It's difficult for me to see how you can satisfy the needs of the Spiny Eels and the Mbuna in the same
system, even hoping that the Spiny Eels will be smart enough to avoid being bitten or harassed by aggressive cichlids.>
My choosing cichlids was dependent on the ability for the eel to thrive, and they all claimed the crushed coral was not so coarse as to damage him.
<Coral sand probably won't scratch him, but it's far from ideal.>
Today he's hanging out over the aerator bubbles and he's jumped into the filter once (he only did that when I treated the tank with Pimafix and it irritated him) so I know he's not happy.
<Indeed.>
I really can't set up another tank, but I want to see him where he'll be happy, and he likes a lot of space.
Thanks for your time
<Here's my workaround. You have so far only Yellow Labs, right? Go back to a regular planted community tank. Yellow Labs have been bred so much in captivity known they should adapt to such conditions. Keep the pH around
7.5, keep the hardness around, say, 12-15 degrees dH, and make sure the water is well oxygenated. Use plants that do well in such conditions (most will be fine). Use soft silica sand on the bottom, and arrange some rocks in heaps for the cichlids to use, while leaving plants in other areas.
Don't get any more Malawi cichlids (at least not without talking to me first!) and just stick with species that should adapt to such conditions.
All else being equal, I'd expect such a community to just about work.
Yellow Labs are hardy and not aggressive, so compared with Malawi cichlids generally, they're fairly good in communities. You will need to feed the Spiny Eels at night to make sure they get enough to eat, but other than that, I can't see any major problems. Not textbook cichlid keeping, but viable. Cheers, Neale.>

Re: Peacock Eel looking pale   2/3/09
I apologize for all the questions, but...
I forgot to add that I also added 2 tablespoons of salt to my 55 gallon tank on Saturday (advised by the fish store guy after checking the water) and I wondered if the salt would irritate him more than the pH which was increased from 7.8 to 8.2. Our house has a water softener, which was never a problem before. If I do some slight water changes will this help him until I can figure out what to do? Will the salt burn his skin, or is the alkaline just way too high?
Thanks, and again sorry for all the here and there questions
<Who told you to add salt to a tank with Malawi cichlids? There's a fair consensus that salt is one cause of Malawi Bloat, and should not be used as an additive in this way. As a component alongside Epsom salt and baking
soda, marine salt mix can be used to create a home-brew Malawi salt, but it should not be used alone. You also shouldn't use water from a domestic water softener. Very bad for fish. Spiny Eels are actually fairly tolerate
of salt, and some species occur in brackish water. But just to be clear:
use plain, un-softened tap water, with no salt, in your aquarium (but with dechlorinator, of course). Cheers, Neale.>

Re: Peacock Eel looking pale   2/3/09
THANK YOU SO MUCH!
For future reference, what other types of cichlid can I add. I want to stay with the less aggressive. Are "electric blue" or "peacock" ok? They were suggested by the fish store.
Thanks,
Beth
<No, I wouldn't go with Aulonocara spp. in the tank I described earlier.
Even the Labidochromis is pushing it, but they're fairly small, peaceful and adaptable. To be honest, I wouldn't add any other cichlids until I had seen the tank running stably for a while, three months at least.
Concentrate on midwater things if need be, barbs and the like. Cheers, Neale.>