Fantail goldfish/water readings

Question
I have two fantail fish approximately three inches. I've had them for approximately 8 months.  I currently use large charcoal filters in a whisper filter.  All levels seem to be ok except for a reading of <6.2 for ph and nitrates at 40 or>.  I feed them pellets in the a.m. and peas in the p.m. so they are pleasantly plump and get upset if they're feedings are fewer and farther between.  The water is somewhat cloudy today after yesterdays water change.  They don't seem to be in distress.  Before the water change and right after I did notice one fish swimming upside down in a low area of gravel against the glass at the bottom of the tank.  After coaxing with net she darted away.  Is this behavior normal?  What can I do to get rid of the acidity in the tank and to bring nitrate levels down?  Should I be alarmed with these levels?  I get upset when I think that they're at risk.

Answer
Hi Lisa;

Weekly water changes with gravel vacuuming is the key to goldfish health. Nitrates are only removed by replacing water. The pH will stabilize as a result of cleaner gravel too. Replace 25% of the water and vacuum the gravel every week. Goldfish are very messy guys that just need plenty of cleaning and lots of room too. For two of them to thrive they need 20 or more gallons. If your tank is smaller, time to upgrade. Those guys are getting bigger and will grow to at least twice their current size.

Sometimes the water will get cloudy after a cleaning due to the bacteria balance being disturbed. Try to avoid replacing the filter media too often. Rinse the pads in a container of tank water to remove crud but it will preserve the beneficial bacteria. This beneficial bacteria clings to the filter pads.

Avoid overfeeding too. Twice a day is okay, but limit the amount to no more than they can totally consume from all areas of the tank in 2 to 3 minutes. More food than that can cause digestive problems, even when feeding peas daily. Too much food is also a major cause of low pH and high nitrates. If you were to feed them once a day, they could eat for 5 minutes, but twice a day should be for 2 to 3 minutes. The idea is to let them feed for a total of 5 minutes every day with no leftovers.

Your little guy that was upside down may have just been "stuck". Those little round guys can get a bit disoriented sometimes. He may have overeaten or swallowed too much air while eating too. It can cause gas in the belly so their bellies float up a bit. Hopefully he's okay and it won't happen again.

At Your Service;
Chris Robbins