Fishkeeping answers

21 min read

Got a fishkeeping question? PFK’s crack team of aquatics experts are on hand to answer whatever you need to know...



Peter is our disease expert. Send questions his way if you have pathogen problems.


Bob is a master of fishkeeping general knowledge and community tanks.


Jeremy is more than adept when it comes to cichlids, goldfish and marine species.


Aquascaping prodigy Jordan is the man to go to for all your planting issues.


Max is like a living, breathing search engine. Cichlids are his speciality.


Neale is the man for your technical queries. He loves brackish fish, too.


Dave is a consultant for the Tetra Advisory Board and a research fellow at Keele University.

MARINE Can I save this coral?

Healthy bubble coral.

Until recently I had an amazing bubble coral measuring about 12cm across and it looked really happy. But I’ve noticed that it seems to be shrinking and I can actually see the skeleton of the coral. Is it doomed or is there anything I can do to stop this getting worse? Would increasing water flow around the coral help?


JEREMY SAYS: First test salinity, temperature, KH, calcium, magnesium, nitrate and phosphate. You need to be aiming for 1.026 s.g., 25°C, 7-8dKH, calcium 400-500ppm, magnesium 1350-1500ppm, nitrate less than 40ppm, and phosphate 0.04ppm. Next, I would invest in an ICP test to give you an expert analysis then send it away, to make sure that your levels of trace elements, like strontium, iron, iodine, zinc and manganese, are where they should be. Correct as necessary to ensure the water is perfect.

If all is good on the water parameter front, have you fed the coral lately? Turn the pumps off and squirt some amino acids, phytoplankton, Reef Roids, Artemia, Mysis and LPS pellets over it and see if it reacts and ingests them.

Make sure the coral is at least 15cm away from all other corals. Although Plerogyra can send out aggressive sweeper tentacles, they can be victims of attack too.

Take the coral out and dip it in a coral dip solution. Bubble corals are prone to flatworms, which can get right into the folds of the flesh and irritate them. Hold the coral upside down in the dip and shake it to see if anything comes off. If you find flatworms, the coral will need weekly dips until they are gone. A scooter blenny and/or a six