can someone explain

[chloebakes]

hi guys can anyone help. i found a dead mollie in my tank tonight. but i have tested water for all the bad things and my water quality seems to be fine i just thought it might be sick then until i found another fish dead. i am making frequent water changes and all the other fish seem to be fine. does anyone know why this is happening?

[AngelMom]

Welcome to the forums!

Unfortunately, no one here can help you without more information. You need to list the water parameters (at a minimum ammonia, nitrite, nitrate, pH and temp) as well as your maintenance and water change schedules (how often, what is changed, and how much is changed, etc).

I can tell you that both your tanks are way overstocked, so problems are not unexpected. There are many good articles here (click the link for aticles at the top of any forum) and many of the mods and members have links in their signatures.

[crazyred]

Welcome the Aquarium Pros!! I agree with AngelMom, your pretty overstocked. Your shark is a fairly aggressive fish for your tank and could be harrassing the others to death. He will need a way bigger tank the 150 L. We do need more information to help. Of major concern is how often do you do water changes? With an overstocked tank they need to be performed very frequently to help maintain water quality. Please post your parameters ASAP so we can help.

[Jay+]

This is not the first post recently on the theme of Molly Death or Illness.

With the water parameters info, I would be curious as to amount and frequency of water changes. I am beginning to understand that mollies are sensitive to high TDS.

A KH and GH reading.

Nutritional Information? What are you feeding? I understand that Mollies require substantial vegetables or algae in their diet.

Black Mollies are native to brackish, Hard and Alkaline water. Breeders add salt to their ponds and then condition the fish to fresh water before they ship them. “A molly that then goes into tap water or soft acidic water will more than likely develop some disease and die.”* I know from years of experience that I cannot keep black mollies in my tank because of my soft slightly acid water, even though it contains a high salt content because of geography.

I am beginning to think a black molly is not as easy to keep as advertised, at least in some water sources.

*Dr. David Ford 2002, Practical Fish Keeping

Jay

[crazyred]

Very interesting. I knew mollies were eventually brackish, but I never really thought of this angle. They could be dying sooner because of the low salt content of some if the tap water out there.

We kept them successfully when I was growing up, but out in West Texas the water coming out of the tap may as well be sea water it's so salty.....I would dare say that the tap water there is darn near brackish.

Interesting point Jay...thank you.

[Jay+]

Well not entirely salt although I think there is a connection.

I think the TDS (total dissolved solids) and the Alkalinity and Hardness of the water are stressing the molly enough to weaken its natural immune systems and it becomes more prone to disease. I think it could be an osmolality issue of some sort.

[Jenn]

I've posted this before. Mollies guppies platys are being way overbred, bred too young, interbred etc. In my city here, I've only been turned down by one petstore (for purchasing my babies). None have asked any questions, or tested my water--they barely look at the fish. I don't think that the problems with these fish can be put to just one thing. The fish was probably sick when you bought it.

[AngelMom]

Yes, illness or genetic problems at purchase is always a possibility, but without the water quality and regular maintenance information, there is no way to be sure.

This is why the sticky is at the top of each forum, to make sure all the information is included in the original post to reduce the "20 questions" process, but no one seems to want to read it. Sigh.

[lloyd berg]

there seems to be something 'inbred' about black fish. the black angels are quite delicate also. IMHO.
-remember to keep your water hard and alkaline. build the salt content 'gradually' to brackish conditions (if desired) with marine salt-not table salt.(mollies can be kept in full marine conditions if acclimated properly). and keep the temp. in the low 70's. HTH.
(stickys don't work, angelmom. most of us are looking for shared opinions. not printed 'lectures'. ;)

[AngelMom]

The sticky I was referring to does not have a "lecture" on anything......it merely informs the user of the information we need to help the poster get the information we need. It's the one titled: "Important!
Please Read Before Posting".

[lloyd berg]

sorry, angelmom. i never read it either. :D

[AngelMom]

LOL - 50 lashes with a wet noodle for Lloyd! :D