My new fish tank is cursed.
Iíve had a Convict Cichlid in the same 10-gallon tank for eight years with absolutely no problems. He is approximately the diameter of a softball, so I decided to upgrade him to a larger, 30-gallon, tank. That was nine months ago and heís been swimming in ammonia ever since. Iíve done everything that I know to control this problem, and it still persists. Here are some of the details:
Ammonia and water chemistry:
The total ammonia levels are usually off the scale of my test kit (greater than 8 ppm). Sometimes Iíll test the water after a partial water change, and the level is still at the very top of the scale, which tells me it was over the scale before the dilution. Nitrate/nitrite levels are usually zero. pH is usually around 6.4 (even though I use a 8.0 powder buffer). There are times Iíve been able to get the ammonia levels as low as 0.5 ppm, but that was usually only after a period of very low feeding and several water changes. I have a color-strip meter inside the tank that indicates the level of only the harmful ammonia ion. According to this meter, although I have very high levels of total ammonia (as measured by several test-kit brands), the level of toxic ammonia is sometimes ďlowĒ, but usually ďlow-mediumĒ. I attribute this to the slightly low (6.4) pH. I think this is the only reason my fish is alive (albeit rather ill). The temperature is the green zone, mid- to high- seventies.
Iíve tried different strategies over the past nine months. At one point I was doing 33% water changes daily. This sounds excessive, but was one of the only effective ways to keep levels low. I worried that may be too frequentÖperhaps too frequent to allow beneficial bacteria to take hold. Therefore at other times I stuck to weekly 33% water changes in the hopes of not flushing out the colonizing bacteria before they took hold.
I started out with a bio-wheel filter designed for a 30-gallon tank. This was grossly inadequate, so I added a second filter also rated for a 30-gallon tank. The second filter was not a bio-wheel, but instead pushed water through three stages (mechanical, carbon and bio-substrate). The second filter eventually became clogged several months ago during a bacterial bloomóso clogged that it became inoperable, so I replaced the second filter with another bio-wheel. I therefore had two 30-gallon bio-wheel filters. The wheels eventually became colonized with a greenish film, which I assume was the beneficial bacteria. I would change the carbon filters about once per month. I actually only changed one carbon insert at a time so as not to remove too much biomass all at once.
At one point both bio-wheels became clogged during a bloom. The intake tubes, the carbon inserts and everything else became so clogged that the water flow was reduced to a trickle. The bio-wheels dried out. As I proceeded to clean the two filters I noticed a very disgusting orangish-brown slime in each of them. It smelled so horrendous that I instantly threw both of them out (more on this topic later). I decided that bio-wheel filters are useless and instead decided to go with the system I currently have. I removed all of the gravel and installed an under-gravel filter system (which is the type I had in my original ten gallon tank). I also installed a Fluval canister filter, which has several levels of filtration, two stages of carbon and one stage of those white ammonia-absorbing rocks. Iíve had this dual-filtration system for about two months now, and yes I still have at least 8ppm of ammonia.
When I first installed my Fluval canister filter, I decided not to touch it for 1 month, in order to allow it to do its thing and hopefully colonize. After one month, I opened it to check on things. I noticed that the white ceramic particles, which are meant for bacteria to colonize had begun to get some spots on them, but were definitely not saturated with colony; they were mostly still white. The first (mechanical) stage is a sponge, which was coated with a greenish-brown slime. I donít know if that was colonizing bacteria or not, so I left it alone.
No solid waste or rotting food:
I also suck up any particulate matter or detritus from the bottom of the tank with a water vacuum whenever I do a water change, so I do not have any solid waste or rotting food in the tank. No live plants either.
My fishís symptoms vary over time. Before I realized I had an ammonia problem he began to swim in circles and became spastic. At times he would remain at the bottom of the tank,listless. Most of those problems clearedóto an extentóonce I began trying to manage this problem. At other times his fins have been eaten away (by some kind of pathogen I presume), and he has chronically had hole-in-the-head disease. I believe this is because his immune system has been compromised due to ammonia and malnutrition at times. At one point he lost most of his color and became really sluggish. I immediately increased his food amount. His color and behavior improved after this, but at a cost of soaring ammonia levels. I am constantly trying to toe the line between not giving too much food in order to avoid ammonia, but not giving too little in order to avoid starvation. As a result, his symptoms vary over time.
What do I add to the water:
With every water change, I add an appropriate amount of water conditioner, usually aquasafe brand. I also add an 8.0 pH buffer powder (an amount appropriate for this size tank). I previously used a 7.0 buffer of a different brand, but this factor seems to have no bearing on the issue. I also add the recommended amount of ďAmmo LockĒ chemical (about a capful every other day). If you are not familiar with Ammo Lock, it is a chemical that does not eliminate ammonia, but it binds it into a form that is harmless. Sometimes I add more than the recommended amount of Ammo Lock, particularly if the ammonia levels become drastic. I also add capfuls of solution that contains beneficial bacteria designed to speed up colonization. Iíve used a few different brands. At one point I also added a lot of those white rocks that absorb ammonia. I poured the rocks into filtration bags and put the bags in the tank. This did very little to help and I eventually stopped using them.
Iíve had a couple blooms, and I think they were blooms of beneficial bacteria. The water would become cloudy, my fish would start breathing heavily (low oxygen as the bloom is breathing a lot of it up), and shortly after that my filters became clogged. I also had some dark-green growth on all sides of the tank. Iím not sure if it was the beneficial bacteria or algae. It was the same color as the stuff that had colonized the bio-wheel, and I think it was around the time I had added an anti-algae tablet. The dark-green stuff would sometimes come off in sheets/strips; I do not know if bacteria will adhere that way or only green algae.
I was initially overfeeding him 2 or 3 frozen brine shrimp pellets per day (this is what Iíve been feeding him for the past eight years). Once I realized this was too much, I drastically reduced his feeding to one medium sized Bio-Gold brand dry cichlid pellet (the pellets are around 3 mm in diameter). I feel that this is not enough food. Sometimes Iíll give him two of those pellets per day, but if I give too much the ammonia levels go even higher, so I am trying to strike a balanceÖnot so much food to raise ammonia, but not so little that he is undernourished.
Iíve never had problems with this fish in his old 10 gallon tank. I wish I had kept the tank, I would totally put him back in that one; I donít know how much longer he can withstand this toxic tank from hell. Itís been nine months, and Iíve done everything I can imagine. So my question is simple. WTF?? Seriously, WTF?
I actually have a second question, which may be related to this, but it is too long to add to this thread. It is about an extremely horrible-smelling brown slime that I have found in the tank. I'll try to title that thread "brown slime, horrible smell", or something similar.