Question about Bichirs and Nitrate levels in my tank

[vonkster]

I currently have a 75 gallon established tank with two gouramis, 4 silver dollars, and two Bichirs. The gouramis and bichirs are maybe 2-4 inches long and the silver dollars in my tank are about 3 inches long. I have an undergravel filter and a magnum 350 canister filter for filtration. I feed my fish a combination of cucumber, freeze dried blood worms, brine shrimp, blood worms, and Tetrafin tropical flakes. All parameters in this tank are mostly normal (nitrites/ammonia are 0 ppm - ph is around 7.8).

My first problem is that I have an unusually high level of nitrates in my tank (around 40 ppm - maybe higher). I cut the amount of food I was giving my fish to see if overfeeding was causing the problem - this did not work. Right now, I am doing 50 percent water changes about once a week - at one point, I was doing 50 percent water changes twice a week with no improvement in the nitrate levels. Anyone have any additional ideas I might try to bring my nitrate levels under control?

As a side note, this problem seemed to start about the same time diatoms started growing in my tank - however, diatoms feed off of nitrates so this should not be causing the problem.

Secondly, my Bichirs do not seem to be interested in eating in my tank. Everytime I chase them near some blood worms I have left for them, they don't seem interested in eating them. What can I do to get them to eat on a regular basis?

Thanks in advance for your help.

 

[clearancepuppy]

Not sure about diatoms... beyond my level.

Keep the water changes up and definitely increase them for a while to get a handle on the situation. The first bichir I had died because I just did not know about how important regular water changes are. I did have it for several years and it got quite big.

The one I have now is healthy as a horse and likes frozen brine shrimp more than frozen bloodworms. You might try some live earthworms. They are true hunters and at least like to think they are sneaking up on live prey lol.

You can also see if it will take some shreds of cooked chicken or beef. Just try a very small amount. Leftovers can cause problems.

I can tell when it needs to eat as it starts sneaking up on snails with the back fins raised on high alert . I had to remove the cories as it acquired a taste for them.

You said you have an under gravel filter. I have switched to sand as it is much easier to clean than gravel. I've never had an under gravel filter but have not heard good things about them.
Another idea is to use some polyfill batting as one part of your canister filtration (I have seen it recommended on here, can find it at Walmart, about $4 a bag...Fairfield is the brand).

I wonder what your tap water test levels are. Also, I am wondering if some live plants would help. Best of luck to you.

 

[Hholly]

I have heard that under gravel filters can be a source of nitrate buildup. It can also be your tap water.

 

[vonkster]

I have tested my tap water and it is around 5 ppm for the nitrate level. In addition, I own a couple of other tanks that are having this problem (high nitrate levels)- they do not have undergravel filters.

 

[Hholly]

Do bichirs have a huge bio load? Seachem makes some good products that can help some. Purigen and I forget the other... They absorb nitrates in your filter you'd have to run it in a HOB.

 

[tyretrack eel]

Hi, been keeping fish 40 years now,still keep bichirs great fish,regards the Nitrate reading,I would get rid of undergravel filter as they over a period of time can get clogged up and cause planaria infestation,go with sand as a substrate no deeper than 1.5 inches and stir every 2 weeks or so to stop any gas build up and get a bigger external power filter as the bigger the filter the more bacterial beneficial filtration you will have to compensate as your fish get bigger,also check your water supply as some areas are higher than others for Nitrate reading,you may also like to consider purchasing or indeed making a Nitrate reactor,keep up with 50% water changes and feed once a day,hope some of this is of help.

 

[vonkster]

So I put both bichirs in a breeding trap and placed half a cube of spirulina brine shrimp in the breeding trap with the bichars. They still are not eating after trying this for two days. Any other ideas or suggestions?

 

[vonkster]

Ok, so I have a new idea as to what is causing the high nitrates in my 3 tanks. I use crushed coral to help keep the ph in my tanks at a reasonable level. I suspect the ph of my tap water changes and therefore, I appreciate knowing that my ph will be ok whenever I do a water change.

However - I have also read crushed coral can generate high nitrates - if this is what is happening, will the use of Seachem Matrix be enough to stop the nitrate buildup created by the use of crushed coral?

If you guys recommend removing the crushed coral, what other products would you recommend to change my ph if the ph of my tap water happens to be too low or too high?

 

[Hholly]

What is the natural pH of your water? Aragonite can do the same as crushed coral. So can limestone. But I had never heard that about the coral raising nitrates. Weird.

 

[vonkster]

Crushed coral is a problem waiting to happen
Here is a link that explains the negative effects of crushed coral.

The ph of my tap water is about 7.4; however, this parameter is subject to change.

 

[Hholly]

Did you add the coral when it was a new tank? New tanks are more subject to swings in pH. Perhaps now, it might be stable if you remove the coral. You could add some limestone rocks if you want too.

 

[Hholly]

That link is talking about using coral as a substrate. That's a big difference from a small quantity in your filter. But again, if you don't think it's good, take it out.

 

[tropical-fish]

I would try feeding the bichirs some type of sinking carnivore pellet instead.