Ichthyologist Rahul G. Kumar was part of a team that studied the fresh water fish of the Western Ghats for an exhaustive book on the subject. Rahul talks about the venture and his work as an expert on fish

Rahul G. Kumar's unassuming house at Maruthankuzhi Junction in the city is home to Peruvians, Colombians, Brazilians, Africans... They reside in 45 aquariums in his home.

In fascinating colours and shapes, the fish lends colour to the space that Rahul has created in a shed in his compound while a room in his house also has aquariums containing fish of myriad kinds. Scientific and common names of species and sub-species roll of his tongue with ease as you scramble to get the spellings correct.

Rahul's fascination for denizens of the deep goes beyond mere hobby and aquariums. A natural scientist with a post-graduate degree in Environmental Science from the University of Mumbai, Rahul smiles when he says that it was a childhood fascination, which began at the age of five when he got his first aquarium. Later, it developed into a passion for the natural world.

Currently pursuing a doctorate in Ichthyology from Madras University, Rahul says he realised that it was fish, and specifically fresh water fish, that fascinated him and so he left his studies in environmental engineering in the United States to return to India. As MetroPlus catches up with him, he is in the middle of preparing a presentation for an international delegation that will be in Kerala. He was part of a team that has just wrapped up a book on the freshwater fish in the Western Ghats, which should be out by the end of the year.

“After I returned to India, a lot of well-wishers felt that I should work on such a book as there was nothing exhaustive on the subject in the past 15 years or so. Most of the dependable books were written by British naturalists working in pre-Independent India,” explains Rahul reeling off the names of authors, natural scientists and writers who had written on the subject.

“Francis Day, T.C. Jerdon, and W. H. Sykes were British army naturalists who did fairly extensive documentation of the fish in Malabar, Kochi and so on. But most of it was in the 19th century. Indian authors like J.C. Jayaram and A.G.K. Menon had also published books on the subject.

“The last book, I think was by J.C. Daniel, written about 15 years ago. What we are doing is specifically on the fish in the fresh water bodies. There are 44 rivers just in Kerala and that is without counting the ponds and lakes. So I felt it was an interesting area of work. Although there were books on the birds and the mammals of Kerala, there was nothing much on the fish in the region,” he explains.

Over two years, the study covered the region south of Gujarat and moved all along the coast to Kerala, Karnataka and Tamil Nadu. Two years of hard work and long treks!

Rahul remembers a four-hour trek to a waterfall near Shimoga. By the time the team reached their destination, their feet were covered with leeches. “We pulled them off our feet and at the end of it, it looked like there was a bloody sacrifice or something,” he says, showing the scars on his feet.

Another time, they were trekking along the edge of the Mudumalai wildlife sanctuary along with a forest guard who ensured that the trip turned memorable as he kept pointing to certain spots where wild elephants had gored unwary travellers. Rahul remembers how at every turn they were looking over their shoulder, expecting to see a wild bull charging at them any moment.

What a catch

“When we began the study, the assumption was that there were between 270 and 290 species of freshwater fish species in the Western Ghats but our work suggests there are more,” he says.

Recently, Rahul was chosen as technical adviser for a BBC team that was filming Karimeen fishing in the Vembanad. Instead of a net, the fishermen drag a long rope along the bottom of the lake. The Karimeen immediately dive into the mud to hide, two fishermen swimming behind the rope catch the fish. Rahul says this ingenious method of catching Karimeen is indigenous to Kerala.

So does the ardent fish lover eat it? “Oh, every day. The ones I eat are different from the ones I rear!” he says.

For new fish keepers…

Get the largest tank you can. The more space there is, the happier the fish will be. Also, length and width of the tank are more important than height.

Invest in good life-support equipment. This includes air pumps and filters. Canister or hang-on-the-back type filters are better than undergravel or power filters. A good rule of thumb is to keep about 70 per cent of your budget for the tank and filter and the rest for fish and decorations. If you have a good filter, just replace about 10-25 per cent of the water in your tank once a week and rinse the filter medium, you don't have to change all the water.

Do not mix goldfish and koi with other fish. These two varieties very long lived if properly maintained (there are koi that are supposed to be over a 100 years old, in Japan) and do not do well in the company of faster moving or aggressive fish.

Resist the urge to keep adding fish to the tank.

Don't waste your money on so called “cleaner fish”. All they do, at best, is scrape algae off the glass.

Discovery of a new species

The excitement of stumbling on a new species is something indescribable, he says.

“It seems to be just another day and suddenly you spot something that is not supposed to be there!” As it happened when they found what looked like a new kind of fish in Wayanad during the end of last year. “We sent a specimen to the Zoological Survey of India. They had also come across the same kind and when the description was published, my photograph of the fish was used. It has been named as Puntius nigripinnis.”