A bit of Glassfish confusion...

keeping any fish in a condition that is not natural to them is making the fish suffer. Alot of fish can *live* in conditions not natural to them but they're definately not doing well.


Glassfish do need BW, in fact a BW fish in FW will significantly shorten it's lifespan and it will have a jeopardized immune system.

As long as the water conditions are kept in check the glassfish can live short period in the FW tank.

Make SURE to cycle the tank before moving the fish.

Welcome to the fantastic world of brackish fish! As you learn more about the limited, but exciting, variety of fish available, I think you'll be happy you stumbled into it. A point of encouragement, keeping a brackish ank is no more difficult that keeping a FW tank.

You did not mention the size of your tank, filtration, or the other fish in tank. This info will help us in advising you on your situation.

I have kept glassfish in my community tank with success. It has some crushed coral to maintain hardness and alkalinity and about 1.005 specific gravity (1.000 is pure fresh, and ~1.024 is marine). I recommend some live food for long term health. Mine seem to prefer diced earthworms, mosquito larvae, and raw shrimp mushed up (in small amounts to prevent tank pollution).

I would recommend you start on Neale Monk's homepage. He is something of a brackish guru, and his site is full of useful info. He is currently working on a book, as well.

http://homepage.mac.com/nmonks/brackfaq.html#BM6c

Here is his take on glassfish:

Periodically, glassfish are sold which have been injected with brightly coloured dyes. Besides being very cruel, this process weakens the fish and may make it more susceptible to disease. Please don't buy these dyed fish.

Glassfish are small perch-like fish which are found in salt and brackish water around the coastline of tropical Asia and Australia. A number of the Australian species have become strictly freshwater fish, but are otherwise similar in needs to the brackish water species. They all need a quiet, well filtered aquarium and regular feedings of live food. They are a group of fish which appear not to do well on flake foods, even if they seem to eat them readily. Possibly some necessary nutrient is missing. Many have exquisite transparent bodies within which every bone can be seen. In good condition they are among the greatest jewels of the aquarium.

Maintain in a planted aquarium, but with open spaces in which the fish can swim. A specific gravity of 1.002 to 1.010 is sufficient for most species, but by and large they will adapt to most conditions. An alkaline pH is important, as is a high degree of hardness. These fish need warmth, around 25 C (75 F) outside of breeding.

The common glassfish Parambassis ranga, often referred to as Chanda ranga in older books, is a small, compressed fish up to 8 cm (3 inches) long. It is found in India and Sri Lanka, where it inhabits a variety of coastal waters. Consequently it adapts well to a variety of conditions, provided the water isn't too fresh. Being rather timid, they prefer to be in good sized schools of around ten or more individuals. If kept in smaller numbers they can be very shy and refuse to feed. When healthy, the males develop bluey-white edges to the anal and dorsal fins. Keep the tank well planted if possible, using any hardy plants such as those recommended for bumblebee gobies. Common glassfish are quite easy to spawn when in good condition. The trigger is an increase in temperature to 28 C (84 F) together with sunlight, especially in the morning. Raising the fry is much more difficult. The eggs are scattered among plants and ignored by the parents; it is probably best to remove the adults and use an antifungicide in the tank. Feed the fry on infusoria at first.

Larger than the common glassfish is Wolff's glassfish, Parambassis wolffii, which can reach 20 cm (8 inches). It is not as commonly traded, probably because it gradually becomes less transparent as it matures. Otherwise it is a handsome fish, but as yet not spawned in captivity. This is partially due to the rarity with which schools of mature specimens are kept. It occurs primarily in fresh rather in brackish water. Being rather large fish, allow them plenty of space.

The most delicate glassfish is also the most desirable. This is the filament glassfish Gymnochanda filentosa, similar in size and habit to the common glassfish but with the males possessing greatly extended anal and dorsal fin rays. Not as frequently spawned as the common glassfish.

Verify that you have glassfish, and not glass catfish. Different animals, different needs.

Congratulations on your decision.

With regards to your filtration, I assume the penquin has more than just the biowheel, such as filter media (floss or sponge) or carbon? Do you use an undergravel filter? Do you use any gravel at all?

I would advise that you seed your new tank with biomaterial from your old tank (after dechlorinating, of course). Several ways you could do this. My favorite is to vacuum the gravel and pour some of the muck into the new tank. More subtley, you may want to do a 1/3 water change and put the used water in the new tank. Or you could put the penquin filter material, or the filter itself, in the new tank ( the old tank should be stable enough to seed a new filter quickly, though I wouldn't feed for a few days).

You obviously have several options and the luxury of a ready source of beneficial bacteria! Just watch your ammonia levels and add your glass fish after the spike returns to unreadable. You may get no spike at all and you could just add them after 7-10 days if there is no activity on your testing.

Then start adding MARINE salt. You can raise the SG by 0.002 every week or so safely (probably quite a bit more, but you're in no hurry, really, and you don't want to shock your fish or your bacteria). I would take it to 1.005. It has worked for me, and most of the small peaceful brackish fish that would make good tankmates for your glassfish do well. Read neal's page above for more info.

Invest in a hydrometer. The cheap (~10-15$) plastic ones that measure all the way to zero do well enough (marine fish keepers only have interest in a range of 1.018-1.030 or so, so be sure the one you buy goes down to 1.000). Even better, buy a cheap refractometer on ebay or here for 35$ (that's what I did)

http://www.drsfostersmith.com/general.cfm?gid=295&ref=2020&subref=AE

Let the little guys settle in for a while, then start adding tankmates. I recommend, depending on the size of the tank, bumblebee gobies, killies, guppies, or mollies. The constant fry supply from the latter two make great food for the other fish!

Good luck!