Marisol Vandekamp

You set up your aquarium, added your fish, and now you notice something strange. They all crowd on one side while the other side sits empty. If you are wondering why fish are avoiding the filter side of the tank, you are dealing with one of the most common questions in fishkeeping. The good news … Read more

I still remember the first time I set up a planted tank for a betta. The water was crystal clear, the plants swayed beautifully, and my betta spent the entire afternoon hiding behind a rock because the hang-on-back filter was pushing him around like a leaf in a hurricane. That is exactly the problem you … Read more

If you’ve ever walked past your aquarium during the day and wondered where your fish disappeared to, only to spot it happily cruising the tank after lights out, you’re not alone. Fish hiding all day but swimming normally at night is one of the most common questions we get from new and experienced aquarists alike. … Read more

When one fish gasps at the surface while the others swim normally, the answer is almost always an individual fish problem, not a tank-wide emergency. I have seen this exact situation in my own tanks for over a decade, and the moment you see a single fish struggling at the top, you need to act … Read more

By Planet Fish | Updated If your fish is floating upside down after feeding, the most likely cause is swim bladder disorder, a condition where the organ that controls buoyancy becomes compressed, infected, or temporarily blocked. The good news is that most cases are treatable at home, especially when you catch them early. Many fish … Read more

I noticed my goldfish spiraling nonstop last spring, and that one moment sent me down a rabbit hole of research, water tests, and late-night reading on fish neurology. If you are staring at your tank right now asking “why is my fish swimming in circles?” I want you to know three things before we dive … Read more

Seeing your fish camped out behind the filter day after day can be unsettling. I remember checking my tank one morning and watching my betta wedge himself between the filter and the glass, refusing to come out for hours. If you are asking yourself “why is my fish staying behind the filter,” the short answer … Read more

I remember watching my cichlid relentlessly pursue a single rainbowfish while ignoring every other tank mate, and I could not figure out what made that one fish so special. After keeping aquariums for 12 years and consulting with ichthyologists, I’ve learned that single-target fish chasing follows different rules than general tank aggression, and the reasons … Read more