would like to convert a unixtime stamp to DateTime

I have a unixtime stamp, stored as a long, that I would like to convert to a DateTime. breakTime(t,tm) supposedly does this, but it does not like my input of a plain long. This is driving me nuts

Surprisingly, perhaps, we can't see the source of your frustration.

DS1307 rtc;
char dtb[100];
DHT dht(DHTPin, DHTTYPE);
SSD1306AsciiWire oled;

unsigned long currentMillis;
unsigned long previousMillis = 0;
long OnTime = 30000;
float h,t,f;
time_t lastFed;

void setup() {
Wire.begin();
Wire.setClock(400000L);
oled.begin(&Adafruit128x64, I2C_ADDRESS);
oled.setFont(System5x7);
oled.clear();

pinMode(DHTPin, INPUT);
dht.begin();

strncpy(dtb,"MM/DD/YY hh:mm:ss\0",100);
rtc.begin();
if (! rtc.isrunning()) {
oled.println("RTC is NOT running!");
//sets the RTC to when this sketch was compiled
rtc.adjust(DateTime(DATE, TIME));
}
DateTime now = rtc.now();

EEPROM.get(0, lastFed);
if(lastFed < 40000000){
lastFed = now.unixtime();
EEPROM.put(0,lastFed);
}

oled.print("CT:");
oled.println(now.format(dtb));
oled.print("LF:");
DateTime lastFedDT;
breakTime(lastFed,lastFedDT);
oled.println(now.unixtime());
oled.println(lastFed);
}

void loop() {

}

Why not post code that will actually compile, using code tags? Give examples of the expected and incorrect output.

Note: it is better to test and debug with the serial monitor, rather than some output device that most people don't have.