1. By:Luke McKeogh,Kyle Lewicki & Jason Asterito
Case Study 1
By:Luke McKeogh,Kyle Lewicki & Jason Asterito

2. Case Study 1 Scenario
Your little sister places her freshwater fish tank on top of her space heater because it is “cold outside”. You notice the fish struggling to survive because of what you now know about dissolved oxygen (DO) and temperature. In an effort to save the fish, you put your sister’s fish in your saltwater tank. A few hours later, your sister is crying because her fish is dead. What happened to her fish and why? What if you took your saltwater fish and placed them in your sister’s freshwater tank? What would happen and why?

3. Freshwater Fish Characteristics
Uptake salt through gills
Excrete little amounts of salt ions
Uptake water and some ions in food
Osmotic water gains through gills and other parts on the body

4. When Fish is Put on Heater
The fish would struggle to survive because the fish would not have enough oxygen. The heater would heat the fish bowl which lessens the amount of dissolved oxygen. The fish, therefore, would not have enough oxygen to survive.

5. Saltwater Fish Characteristics
Gains water and salt ions from food and seawater
Excretion of salt ions from gills
Excretion of salt ions through urine from kidneys
Osmotic water loss through
gills and other parts of the body

6. Freshwater Fish in a Saltwater Tank
When placed in a saltwater tank, the freshwater fish would struggle to survive. This would occur because the water molecules contained in the fish’s body passed through the cell membranes of the fish which cause the fish to lose water. The fish would not be able to rid its body of enough salt quick enough. The fish would become dehydrated because of the process of osmosis. This process would cause the water inside the fish’s cells to go to the saltwater solution.

7. Saltwater Fish in a Freshwater Tank
When placed in a freshwater tank, a saltwater fish would not be able to survive. Saltwater fish excrete salt through their gills and excrete greater amounts of salt ions than freshwater fish. The saltwater fish would not be able to obtain enough salt ions to excrete, which could cause a buildup of nitrogenous waste, including ammonia, which is very toxic. The cells of the fish may also flood as the saltwater fish takes in so much fresh water through osmosis through the gills without having enough salt.