150 Gallon Cichlid tank with many issues

Question
Hi Susan,
I recently set up at 150 gallon aquarium about 5 months ago and it has been nothing but trouble. I cycled it for about a month doing the fishless cycle, once it was done and I was given the all clear I put a new firemouth and salvini cichlid in it both ended up having HITH which I didn't notice right away. About a week after I added my full grown Oscar, pleco and nearly full grown Jack Dempsey. Soon after is when the issues began I have got ick a few times, my nitrates have been out of control no matter how many water changes I do. My jack Dempsey got gill flukes which I got rid of, the salvini was kicking the firemouths butt so I took it out. I have been workin on it closely wih my LFS and one girl that works there has been slowly helping me fix it but there is one major issue that we can't figure out. We think that it is a parasite though. About a month ago my Oscar got dropsy and died. I think what happened was when he got a large cut on his side a parasite that is in he water got into his blood stream and have him the dropsy. Since then I have treated my fish with anti parasitic food and it seemed to have helped but I think that it might be back. My jack Dempsey has gone pale again and my salvini has a slightly swollen abdomen and I noticed a white poo on the bottom of the tank that mixed with the fact that she still has hole in he head, that it could be hexamita. After recently treating my fish for a bacterial infection- which worked- everything seemed fine for a few weeks so I got a fire eel and an unknown fish- its still a baby and I can't remember what they said it was. I'm taking the little fish to my sisters house because I'm sure I'm going to have to treat this tank for something. When I came home last night and tested the water the ammonia was at 3.7, the ph was over 8 and the nitrates were still high. This is with me doing water changes about 3 times a week. I'm sorry this is so jumbled and long winded, I'm remembering things as I go. Basically I need general help on what to do next, I have no idea. Also, I'm wondering if however I need to treat this next can be done with the fire eel in the tank or if I will have to take it out. Thank you so much for any info you can give me.
-Michelle

Answer
Hi Michelle,
I'm sorry to hear about the issues you've been having with your tank and the fish loss... :(

Dealing with HITH is very challenging. Once it sets in, it may take months to reverse. There is a lot of speculation as to what -exactly- causes HITH. After all that I have read and studied about it (and experiencing it myself with a full grown Oscar in the past) I feel strongly that it is primarily water quality related. High nitrates are almost inevitable with oscars and other cichids. Its very easy for the nitrates to build up sky high in no time when dealin with larger, heavy waste producing fish.

Dropsy is generally a symptom of various triggors and not a disease in itself. Its typically a malfunction of the kidneys causing the fluid retention and therefore the swelling...  

Swollen abdomens can also be due to internal cysts and tumors. Sadly of course there is little you can do for that. Internal bacterial infections can also cause swelling. These infections are difficult to treat.

Usually -- internal parasites cause stringy-white or otherwise pale poo and the fish usually goes pale and loses weight. He may also refuse food or take food in and spit it out.

The fact that your nitrates are constantly high raises the red flag that this could be the source of your fish issues. High nitrates stress the immune system greatly. And the presence of high nitrates also means a high level or other pollutants we generally don't or cannot measure that also impact fish health.

And now that you have a dangerous reading of ammonia, your fish are very much at risk. Some things I'm going to recommend for your to try are -
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*Test your tap water for nitrates - (If present ,use a water conditioner that neutralizes nitrates along with the other important things such as Seachems' Prime or Amquel + PLUS)

*Thoroughly vacuum the gravel everyday and do a 50% water change. If you can do this everyday that would be ideal. It sounds like your 'biofilter' or the 'good bacteria' have been destroyed by the medication usage given the fact that there is ammonia in present in your tank. Water changes will help get your fish through this dangerous time until the bacteria can re-establish.

*Make sure to not offer any feeder fish to your cichlids. Try to feed a high quality pellet food rich in whole foods and vitamins and for supplements feed frozen foods like krill.

*~HITH can usually be -reversed- by tons of water changes and a healthy diet.
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I hope this has helped! More often than not, fish problems are usually related to the environment. Water changes (and perhaps a good water conditioner) are the keys to reversing and preventing most problems.

This will likely be a gradual process. Remember there is damage being done already to the fishes immune system due to the ammonia and high nitrates. The best thing is to just stay persistant with trying to maintain as clean of water conditions as possible and make sure there are no nitrates in your tap water system adding to the problem.

GOOD LUCK!!
Susan~