eel bw or fw?

1.003 is barely even brackish, no wonder he's ok. I'd be worried about the brackish fish now. 1.003 is WAY too low for most brackish fish, especially those monos. You should have your salinity around 1.010 for all those fish to live long. How long have you had the brackish fish?

Are those mangroves in a sump? How long have you had them? They don't look more than a few months old. I just got four for my SW and they've already grown two new leaf nodes in a month.


Another thing, is that mangroves take the important element of marine salt out of the water column. Magnesium Sulphate, if you don't dose it, it's almost pointless to keep the tank brackish with such a low salinity. If you dose it, you'll notice the mangroves growth will almost double in speed and your more sensitive species will show less stress.
 
I've kept this tank more or less unchanged for over 7 years. Most of my fish deaths over the years have been attributable to specific incidents such as power outages, "buds" who think fish like beer, etc. When I have had monos and scats that get too large (boy they get big after 2-3 yrs), I have brought them to the LFS where they have been acclimated to marine and sold as "oddities" to fish-only owners. I'm lucky to have a cooperative, knowledgable LFS owner who appreciates my business.


I added those mangroves over 3 years ago to my main tank. You can see them from below attached to the driftowood and inserted into the coconut on the bottom picture. I got them as seed pods on ebay from a fella in Hawaii. They grow very slowly, and you can see I must occaisionally nip the meristem or curve the trunk downwards with a rubberband. I read somewhere along the way that theycould be trained thusly and sort of bonzai'd. I always thought it was the relatively low lighting and my trimming/shaping that kept them in check. My lighting is two 48" VHO lamps I trade out every 6-8 mos. Ironically, it's the ones out of direct light that remain the greenest/healthiest-looking. You'll note one to the left in the picture with yellowed leaves burnt at the end. I have since read that they do not like the heat of the lamps, so I have moved all to the periphery.

Interesting point aobut the the mag. I had read extensively on-line about the benefits of mangroves in a sump for marine tank,, but had not read that. I have never kept a marine tank so know little (nothing) about electorolyte dosing, etc. Is MgSO4 a commonly available supplement? Frankly, none of my fish show "stress" :) , but it couldn't hurt to try.

I have been a lurker here for several years, and know your name, as well as ananda, puffer punk, olaf, and the like, and have always enjoyed reading your pearls. Never thought I would be one of the folks getting advice like a newb. I hate to be one of those types that says "thanks for the input, but I am going to continue to keep my oscars, fahakas, and monos in the same 5 gallon FW tank because they've been together for 3 weeks and so far everyone is healthy and they get along great!", but. . .
 
Nobody is trying to force you to do anything, at least your giving your fish somewhat brackish conditions.

Magnesium sulphate is a commonly available product for reef tanks.
As for the lighting, the ones that aren't doing that well are too close to the light. You want them at least 12-14" from the mangroves otherwise they'll be burnt by the lights, which is indicated by yellow/brown leaves which I saw in one of your pics.
 
update:

well, the guy's still not eating even after moving it into a larger FW tank....BUT i noticed that it has some strange white marks on it's body. I asked a LFS about the marks and the guy said it was probably a fungal infection. He gave me some medication and i'm currently treating the tank. It's been medicated for a couple of weeks now and he seems a little more active, but still not eating...and the white marks are still there but not as much. Got any ideas what else it might be?
 
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