Unlimited Money
You can edit the save files manually to unlock everything and give yourself unlimited amounts of money. Just open them in notepad and find the line "resources" under there you have the money and the ecology and science points you can adjust. The save files located in MyDocuments/My Games/Megaquarium/Saves
If you have 1000 money then search for 1000 in your document until you find something that looks like this (your number values will obviously be different);
"resources": {
"money": 240000,
"rankNumber": 11,
"points": {},
"pointChains": [],
"firstDayOfHistory": 1,
"moneyHistoryByType": [
{}
In this example ""money": #" is set to "money": 240000", but if you had 1000 money that number would be 1,000, all you simply do is change that number to your desired value (for example: 999999).
When you reload the save it will use those values. Pretty easy to just unlock everything so long as you have a single tank to tick over the points to the next level on each reload. Or with unlimited money you can build a large tank, stuff it full of animals and get loads of points that way.
Note: If the files inside the Saves folder have no extension, make sure to change your Folder Options to include file extensions (Hide common file extensions) in your System Control.