If the catfish has a strong fishy smell, it has gone bad. You can  also tell by looking at it, if you see areas that appear  discolored, it is likely bad.Finally, press on â¦ it, fresh fish  should bounce back and not feel squishy.1 person found this useful.f the catfish has a strong fishy smell, it has gone bad. You can  also tell by looking at it, if you see areas that appear  discolored, it is likely bad.
Frequency. The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second.The unit of frequency is the hertz (Hz). It is common for kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) to be used when waves have very high frequencies.requency. The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second. The unit of frequency is the hertz (Hz).
Frequency is measured in hertz. The hertz, Hz, is the derived SI unit of frequency. The frequency of a sound wave determines its tone and pitch. The frequency range of a young person is about 20 to 20,000 hertz. The human ear is capable of hearing many of the sounds produced in nature, but certainly not all.requency is measured in hertz. The hertz, Hz, is the derived SI unit of frequency. The frequency of a sound wave determines its tone and pitch. The frequency range of a young person is about 20 to 20,000 hertz. The human ear is capable of hearing many of the sounds produced in nature, but certainly not all.